ALPHA User Manual
1005541
2nd edition, publication date May 2011 © 2011 BRUKER OPTIK GmbH, Rudolf-Plank-Straße 27, D-76275 Ettlingen, www.brukeroptics.com All rights reserved. No part of this manual may be reproduced or transmitted in any form or by any means including printing, photocopying, microfilm, electronic systems etc. without our prior written permission. Brand names, registered trademarks etc. used in this manual, even if not explicitly marked as such, are not to be considered unprotected by trademarks law. They are the property of their respective owner. This manual is the original documentation for the ALPHA spectrometer. The ALPHA spectrometer is covered by one or more of the following patents: US 5,499,095; US 5,923,422; DE 19940981. Other US and international patents are pending.
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Ta b l e o f C o n t e n ts 1
About this Manual . . . . . . . . . . . . . . . . . . . . . . . . 1
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ALPHA & Measurement Modules . . . . . . . . . . . . . 3 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8
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3 4 5 7 8 9 11 11
M easurement . . . . . . . . . . . . . . . . . . Q uali ty Contro l . . . . . . . . . . . . . . . . . I dentification of an unknown Substance Q u a n t i t a t i o n o f a S ample Component .
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No Sa mpl e P repa ration . . . . . . . . . . . . . . . . . . . . . . 4 2 KB r P e l l e t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 Th i n fi l m be tw ee n two plates . . . . . . . . . . . . . . . . . . 4 3
Transmission Measuring . . . . . . . . . . . . . . . . . . 45 5.1 5.2 5.3 5.4
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Sample Preparation . . . . . . . . . . . . . . . . . . . . . . 41 4.1 4.2 4.3
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Quick User Guide . . . . . . . . . . . . . . . . . . . . . . . 13 3.1 3.2 3.3 3.4
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G eneral Technical Feat ures . . . . . . Basic Module . . . . . . . . . . . . . . . . AL P H A -T Mea s u re m e n t M o d u l e . . . . AL P H A - P M e a s u r e m e n t M o d u l e . . . AL P H A - E M e a s u r e m e n t M o d u l e . . . Exchanging Measurement Mo d u l e O perating Spectrometer . . . . . . . . . Ac t i v a t i n g S t a n d - b y M o d e . . . . . . .
G eneral Information . . . . AL P H A -T . . . . . . . . . . . Positioning sample in the ment . . . . . . . . . . . . . . M easuring Sample . . . . .
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. 45 . 46 . 47 . 50
ATR Measuring . . . . . . . . . . . . . . . . . . . . . . . . . 51 6.1 6.2 6.3 6.4 6.5 6.6 6.7
G eneral Information . . . . . . . . . AT R Measurement Module . . . . Pe r f o r m i n g C l e a n n e s s T e s t . . . Placing Sample on AT R Crystal M easuring Sample . . . . . . . . . . Cleaning ATR Module . . . . . . . AT R S pectra . . . . . . . . . . . . . .
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ALPHA User Manual
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51 52 57 57 58 59 60
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Table of Contents
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Ma i n t e n a n c e & R e p a i r . . . . . . . . . . . . . . . . . . . . 6 1 7.1 7.2 7.3 7.4 7.5
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Replacing IR Source . . . . . . . . Replacing Desiccant Bags . . . . Re p l aci ng Wi n d o ws . . . . . . . . . Cl e a n i n g W i n d o w s . . . . . . . . . . Cl e a n i ng S pe ctrom eter Housing
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62 65 67 70 70
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . 71 8.1 8.2 8.3
G eneral Information . . . . . . . . . . . . . . . . . . . . . . . . . 7 1 Available Diagnostic M eans . . . . . . . . . . . . . . . . . . . 7 2 Problem - Possible Causes - Sol u t i o n s . . . . . . . . . . . 7 9
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Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . 93
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Consumables . . . . . . . . . . . . . . . . . . . . . . . . . . 95
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Dimensional Drawings . . . . . . . . . . . . . . . . . . . . 97
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Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
E
Service Addresses . . . . . . . . . . . . . . . . . . . . . 111
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ALPHA User Manual
Bruker Optik GmbH
Chapt. 1
1
About this Manual The ALPHA user manual contains detailed information on the single spectrometer measurement modules in chapter 2. On the basis of different examples the Quick User Guide in chapter 3 provides a step-by-step introduction into the OPUS software, and gives answers to analytical problems. For sample preparation refer to chapter 4 which contains a short summary of the most important sample preparation methods. Chapter 5 describes in detail the measuring in transmission mode and gives information on how to properly position the sample in the sample compartment of the transmission module. Detailed information on what has to be considered in case of ATR measuring, what crystal types are available and how to position the sample on the ATR crystal is given in chapter 6. Maintenance instructions and a description of the steps required when replacing the IR source, the desiccant bag as well as the KBr-window are included in chapter 7. Chapter 8 describes possible spectrometer problems, their diagnosis as well as troubleshooting by means of the OPUS software. The specifications of the ALPHA spectrometer are listed in appendix A, the most important customer drawings are included in appendix B. The glossary in appendix D describes single relevant spectroscopic terms in more detail. For the worldwide Bruker service addresses refer to appendix E.
Bruker Optik GmbH
ALPHA User Manual
1
Chapt. 1
2
About this Manual
ALPHA User Manual
Bruker Optik GmbH
Chapt. 2
2
ALPHA & Measurement Modules 2.1
General Te chnical Features
The ALPHA spectrometer is a small compact FT-IR spectrometer designed for routine applications in the laboratory. Due to its modular design ALPHA ensures highest possible flexibility during measurement. ALPHA consists of a basic module and an exchangeable measurement module. The following measurement modules are available. Module available
Type of measurement
To be used for the following sample types
ALPHA-T Transmission (Universal Sampling Module)
Solids (e.g. plasic films, KBr pellets) liquids, gases
ALPHA-P Attenuated total reflection (Platinum ATR Module; avail- (ATR) able as high pressure module as well)
Solids, liquids
ALPHA-E (Economic ATR Module)
Solids, liquids
Attenuated total reflection (ATR)
The different modules are described in the following. For further information on the single measurement modules refer to chapter 5 and 6.
Basic module
Exchangeable measurement module
Figure 1: Modular spectrometer design
Bruker Optik GmbH
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Chapt. 2
ALPHA & Measurement Modules
2.2
B asic Module
The basic module contains the following optical components:
IR source
low voltage, air cooled lifetime: ±44,000 operating hours
Interferometer
Rocksolid, permanently adjusted
Beam splitter (material)
KBr (standard) ZnSe (in case of high humidity option)
Window
KBr (standard) ZnSe (in case of high humidity option)
Detector
DTGS detector (room temperature)
A permanent online diagnosis of the single components (e.g. IR source, laser, detector and interferometer) facilitates troubleshooting and maintenance. The connecting ports (e.g. power, Ethernet) and the system diagnosis LEDs are at the rear side of the basic module, see figure 2.
A
B
CDE
F
G
H I
J
K
Figure 2: ALPHA rear side - Connecting ports and LEDs
4
Type
Definition
A
USB port
Not available.
B
ETH/LAN port
The ETH/LAN port is used to connect the spectrometer to a computer on which the OPUS software is installed. The ETH port is designed for RJ-45 plugs and complies with the Ethernet standard. To connect the spectrometer to the PC the supplied data cable (cross over, 10Base-T with RJ45 ports) is used. See also the ALPHA installation instructions.
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Bruker Optik GmbH
ALPHA-T Measurement Module
Chapt. 2
Type
Definition
C
TKD LED
The green TKD LED indicates that the interferometer mirror is within the data acquisition range. When data acquisition actually takes place the light intensity changes to bright green. The TKD abbreviation means Take Data.
D
ACC LED
The yellow ACC LED indicates that the network accesses the optics. During transition of measuring data the LED will be light yellow. The ACC abbreviation means Access.
E
DIR/ERR LED
In normal operation mode the DIR/ERR LED flashes slightly red and indicates the scanner movement. If the LED lights permanently bright red, there must be an interferometer problem, e.g. missing laser signal. As long as this LED lights permanently red no data acquisition is possible. The DIR abbreviation means Direction, ERR means Error.
F
Ext. Accessory port This port can be used to connect external optional accessories, e.g. detector, remote trigger etc.
G
TAP port
The TAP male connector includes 10 socket contacts and is used for service and diagnostics only. The TAP abbreviation means Test Access Port.
H
CFG switch
CFG is a fourfold DIP switch: • #1 ON and #2 OFF: DHCP mode - use last DHCP address • #1 OFF and #2 ON: use ON-IP address 10.10.0.1 • #3: stay in boot loader, do not load the application program • #4: reserved The CFG abbreviation means Configuration.
I
SBY/RES button
Depending on how long you press this button you either activate/deactivate the stand-by mode or reset the spectrometer (i.e. restore the initial spectrometer state). If you press this button about 2 seconds, you activate/deactivate the stand-by mode. If you press this button more than 6 seconds, the spectrometer will be reset. The abbreviation SBY means Standby, RES means Reset.
J
POWER port
This port is used to connect the spectrometer to the power supply. Use the supplied power cord with mains adapter. The POWER port is suited for extra low-voltage connectors. Only use power cords which have been approved by Bruker. See also the ALPHA installation instructions.
K
Kensington lock
This optional lock is a kind of safety (anti-theft) lock for mobile hardware.
2.3
A LPHA-T Measurement Module
The ALPHA-T measurement module is designed for measurements in transmission. This measurement module allows to spectroscopically analyze both solids, liquids as well as gases. Bruker Optik GmbH
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Chapt. 2
ALPHA & Measurement Modules
In case of measuring liquid and gaseous samples optional liquid and gas cells are available. These gas cells can be mounted into the sample compartment of the transmission measurement module. For further details on this subject see also chapter 5.
A
B E C
D
Figure 3: ALPHA-T
Definition A
Basic module (with integrated electronics and optics)
B
Lock/release
C
ALPHA measurement module (for spectroscopic transmission measurements
D
Sample compartment lid
E
Status indicator
2.3.1
A L P H A - T s a m p l e c o m pa r t m e n t
The ALPHA-T sample compartment is behind the blue cover (D in figure 3) and can be accessed from the front side.
To o p e n t h e s a m p l e c o m pa r t m e n t . . . • ...reach under the bottom edge of the sample compartment lid and lift it up.
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ALPHA-P Measurement Module
Chapt. 2
A
B C
Figure 4: ALPHA-T - Sample compartment open
Definition A
Sample compartment lid
B
Sample holder
C
Ports for the IR beam passing the sample compartment
For detailed information on how to prepare and insert samples refer to chapter 4 and 5.
2.4
A LPHA-P Measurement Module
The ALPHA-P measurement module is designed for measurements in attenuated total reflection (ATR). This measurement module allows to spectroscopically analyze both solids (e.g. paste, powder) as well as liquids. The following ATR crystal types are available: • Diamond • Germanium (Ge) For further information on this measurement module refer to chapter 6.
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Chapt. 2
ALPHA & Measurement Modules
A
F
B
G
C
D
H
E
I
Figure 5: ALPHA-P
Definition A
Lever to move the anvil up and down
B
Pressure control spot (round recess)
C
Anvil
D
ATR crystal
E
ALPHA-P measurement module for ATR
F
Height adjustment for pressure arm
G
Basic module
H
Status indicator
I
Crystal plate with integrated ATR crystal
2.5
A LPHA-E Measurement Module
The ALPHA-E measurement module is designed for measurements in attenuated total reflection (ATR). This measurement module allows to spectroscopically analyze both solids (e.g. paste, powder) as well as liquids.
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Exchanging Measurement Module
Chapt. 2
The following ATR crystal types are available: • Germanium (Ge) • Zinc selenide (ZnSe) For further information on this measurement module refer to chapter 6.
A E
B
C
F
D
Figure 6: ALPHA-E
Definition A
Knob to press and release the anvil
B
Anvil
C
Crystal plate with integrated ATR crystal
D
ALPHA-P measurement module for ATR
E
Basic module
F
Status indicator
2.6
Exchanging Measurement Module
The three different measurement modules available (ALPHA-T, ALPHA-P and ALPHA-E) can be exchanged. The procedure is the same for all three measurement modules. See the following figure: Bruker Optik GmbH
ALPHA User Manual
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Chapt. 2
ALPHA & Measurement Modules
Step 1: Press the lock on the basic module right down. Note: The measurement module is released from the basic module and the lock stops at halfheight.
Step 2: Pull out the measurement module from the basic module.
Step 3: Push the new measurement module right against the basic module.
Step 4: Press the lock on the basic module once again right down.
Note: The measurement module engages into the basic module, and the lock snaps right up.
Figure 7: Procedure when exchanging the measurement module
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Operating Spectrometer
Chapt. 2
W h a t h a p p e n s a ft e r e x c h a n g i n g t h e m e a s u r ement module? OPUS automatically recognizes the newly inserted measurement module and starts a performance test (accessory test). For more detailed information refer to the OPUS/MENTOR manual.
2.7
Operating Sp ectrometer
The spectrometer is operated by means of the OPUS software. For detailed information on the OPUS software refer to the OPUS/MENTOR manual and chapter 3.
2.8
A c t i v a t i n g Sta n d - b y M o d e
Basically, you can either set the spectrometer to stand-by mode or completely disconnect it from the mains supply by unplugging the power cord. It is recommended to set the spectrometer to stand-by mode overnight. Only in case of longer shut-down periods (e.g. several days) is it advisable to completely disconnect the spectrometer from the mains supply. If the spectrometer is in stand-by mode, it is not switched off completely. There is still some power consumption which is, however, significantly lower than in operation mode as the IR source, laser and detector are switched off.
H o w t o s e t A L P H A i n t o s ta n d - b y m o d e ? 1
Press the SBY/RES button (A in figure 8) at the spectrometer rear side for a short time (about 1 to 2 seconds).
A
Figure 8: ALPHA rear side - Stand-by/Reset key
Bruker Optik GmbH
ALPHA User Manual
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Chapt. 2
ALPHA & Measurement Modules
2
Now, the spectrometer beeps and the green status indicator on the spectrometer top side begins to flash in short intervals. The OPUS status light becomes gray.
How to set ALPHA into operation mode again? 1 2 3 4
12
Press again the SBY/RES button at the spectrometer rear side only for a short time (about 1 to 2 seconds). Now, the spectrometer beeps and the laser, IR source and detector are switched on again. As the IR source warm-up takes about 7 minutes, the spectrometer status indicator is yellow during this period. As soon as the IR source has reached its operating temperature, the spectrometer status indicator permanently lights green.
ALPHA User Manual
Bruker Optik GmbH
Chapt. 3
3
Quick User Guide The purpose of this quick user guide is to enable you to familiarize yourself with the OPUS software within a short period of time and to learn how to perform the most relevant analytical tasks on your own. This chapter describes the procedures for realizing the following analytical task definitions: • Sample Measurement - How to perform a spectroscopic measurement? How to manipulate a sample spectrum? How to save and/or print a spectrum? • Quality Control - Are the delivered goods or the self-made products consistent with the specified quality criteria? • Identification of an unknown substance - What substance is it? • Quantitative Analysis - How much of a certain component does the sample contain?
3.1
M easurement
3.1.1
General Information
It is recommended to perform a measurement using the factory parameter settings. In this case, you can start with the measurement immediately. See the following descriptions General Measurement Procedure. In addition, OPUS offers you also the possibility to adapt the measurement parameter settings (e.g. the parameter value Scan Time) to your special demands. To do this, click in the OPUS wizard with the left mouse button next to the Measurement button and select the option Setup "Measurement"... (see figure 9). As a result, the Setup Measurement Parameters dialog opens. For a detailed description of this dialog window refer to the OPUS/MENTOR manual.
Figure 9: OPUS Wizard - Opening the Setup Measurement Parameters dialog
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Chapt. 3
Quick User Guide
W h e n m e a s u r i n g a s a m p l e , a l w a y s pa y a t t e n t i o n to the following issues: • If the sample needs to be prepared, due to its composition, prepare it carefully and avoid preparation errors. For information about sample preparation refer to chapter 4. • Avoid measurement errors (e.g. the ATR crystal is not covered completely with the sample).
3.1.2
General Measurement Procedure
Generally, the measurement procedure can be subdivided into the following steps: 1 2 3 4 5 6 7
Measuring a background spectrum Preparing the sample, if required Measuring the sample spectrum Manipulating the sample spectrum Performing a peak pick, if required Saving and / or printing the manipulated spectrum Measuring the next sample, if required
How to perform a measurement: 1
Click in the OPUS Wizard on the Measurement button (see figure 10).
Figure 10: OPUS Wizard - Starting a measurement
2
14
The following dialog window opens:
ALPHA User Manual
Bruker Optik GmbH
Measurement
Chapt. 3
Figure 11: Measurement dialog - Starting a Background/Sample Measurement
3
First, perform a background measurement (i.e. a measurement without a sample in the spectrometer sample compartment or without a sample on the ATR crystal) by clicking on the Start Background Measurement button.
Note: When you acquire a background spectrum using the ATR module, first check whether the ATR crystal is really clean, i.e. it is absolutely free from residuals of the previous sample. If your sample needs to be prepared using a solvent acquire the background spectrum of the pure solvent (i.e. solvent without sample).
4 5
The background measurement takes a few seconds. The measurement progress is shown in the lower status bar. Put the sample in the spectrometer sample compartment or on the ATR crystal.
Note: Depending on the composition of the sample (solid, powdery, paste-like, liquid etc.), the sample may need to be prepared before you can put it in measurement position of the spectrometer. For detailed information about sample preparation refer to chapter 4.
6 7
Then click on the Start Sample Measurement button (see figure 11). The sample measurement takes a few seconds. The measurement progress is shown in the lower status bar. Afterwards, the acquired sample spectrum is displayed in the OPUS spectrum window.
Note: If you use the factory parameter settings, the spectrum is stored by default under OPUS path/meas. The file name is identical to the sample name you have entered in the Measurement dialog (see figure 11). If you do not enter a different sample name the file name is incremented with any further measurement.
Immediately after the sample measurement, the OPUS Wizard switches automatically to the Manipulate level (see the following section). Bruker Optik GmbH
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Chapt. 3
Quick User Guide
3.1.3
M a n i p u l a t i n g a S a m p l e Spe c t r u m
After the sample measurement, a spectrum postprocessing may be required to ensure that OPUS yields acceptable evaluation results, for example when you intend to perform a substance identification or a quantitative analysis. For this purpose, OPUS offers a number of manipulation commands. Manipulating in this context means "optimizing" the measured sample spectrum. This section describes the following manipulation commands: • Baseline Correction • Atmospheric Compensation For information about additional manipulation commands refer to the OPUS/MENTOR manual. A Baseline Correction is always highly advisable if the spectrum baseline deviates strongly from a theoretical horizontal line. This phenomenon may occur, for example, when you measure a sample prepared as a KBr pellet. (See also chapter 4, Sample Preparation.) Figure 12 illustrates the effect of a baseline correction. For detailed information about this command refer to the OPUS/MENTOR manual.
Spectrum before a baseline correction
Spectrum after a baseline correction
Figure 12: Baseline Correction
How to perform a baseline correction: 1
2
16
Measure a spectrum or load the file of the spectrum you intend to manipulate by clicking on the corresponding button in the OPUS wizard (see figure 10). Thereupon, the sample spectrum is displayed in the spectrum window and OPUS switches automatically to the Manipulate level. Click in the OPUS Wizard on the Baseline Correction button (see figure 13). ALPHA User Manual
Bruker Optik GmbH
Measurement
Chapt. 3
Figure 13: OPUS Wizard - Performing a Baseline Correction
3
Thereupon, OPUS performs a baseline correction and displays automatically the corrected spectrum in the OPUS spectrum window.
Note: To undo a baseline correction, select the Undo Changes command in the OPUS File menu.
The OPUS Atmospheric Compensation command eliminates H2O and/or CO2 bands from a sample spectrum. These bands result from the ambient air and occur if there is a difference in the H2O and/or CO2 concentration between the moment of the background measurement and the moment of the sample measurement. Figure 14 illustrates the effect of an atmospheric compensation. For detailed information about this command refer to the OPUS/MENTOR manual.
Spectrum before an atmospheric compensation Spectrum after an atmospheric compensation
Figure 14: Atmospheric Compensation
Bruker Optik GmbH
ALPHA User Manual
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Chapt. 3
Quick User Guide
How to perform an atmospheric compensation: 1
Measure a spectrum or load the file of the spectrum you intend to manipulate by clicking on the corresponding button in the OPUS wizard (see figure 10). Thereupon, the sample spectrum is displayed in the spectrum window (as shown in figure 15) and OPUS switches automatically to the Manipulate level.
Note: The Atmospheric Compensation command requires a spectrum file that includes, amongst others, the data blocks SSC (Sample Single Channel) and RSC (Reference Single Channel). (See figure 15.) Otherwise, an atmospheric compensation cannot be performed. OPUS Browser with a loaded spectrum file. This file contains, amongst others, a SSC data block and a RSC data block.
Figure 15: Spectrum before an atmospheric compensation
2 3
Click on the Atmospheric Compensation button in the OPUS Wizard. Thereupon, OPUS performs an atmospheric compensation and displays automatically the atmospherically compensated spectrum in the OPUS spectrum window (see figure 16).
Note: To undo an atmospheric compensation, select the Undo Changes command in the OPUS File menu.
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Measurement
Chapt. 3
Figure 16: Spectrum after an atmospheric compensation
3.1.4
Peak Picking
The Peak Picking allows you a prompt determination of the exact spectrum peak positions, i.e. the exact frequency values (x-values) at which maxima (in case of an absorption spectrum) or minima (in case of an transmission spectrum) occur in the spectrum.
How to perform a peak pick: 1
2 3
Measure a spectrum or load the file of the spectrum you intend to manipulate by clicking on the corresponding button in the OPUS wizard (see figure 10). Thereupon, the sample spectrum is displayed in the spectrum window and OPUS switches automatically to the Manipulate level. Depending on the measurement method, the displayed spectrum is either an absorption spectrum or a transmission spectrum or an ATR spectrum. Manipulate the spectrum, if required. Otherwise, click on the Evaluate tab and then on the Peak Picking button in the OPUS wizard. Thereupon, the exact frequency values, at which maxima or minima occur, are displayed in the spectrum window. See figure 17a and 17b.
Figure 17: a)Peak pick result in case of absorption b) Peak pick result in case of transmission
Bruker Optik GmbH
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Chapt. 3
Quick User Guide
How to perform an interactive peak pick: 1
Alternatively, you can pick peak(s) also interactively by clicking with the left mouse button next to the Peak Picking button and selecting the option Interactive Peak Picking. Thereupon, the following view appears:
Line
Figure 18: Interactive peak picking
2
3
4
20
Using the line in the spectrum window, you can select interactively the peaks of which the frequency value is of interest to you. symbol and move the line To do this, place the cursor on the with pressed left mouse button up- or downwards. The frequency values of all peaks above this line are displayed (see figure 18). Click on the Save button to save the currently displayed peak position values. Thereupon, a PEAK data block is added to the spectrum file in the OPUS browser. Alternatively, you can view the peak picking result in form of a report. The report is displayed below the spectrum window. See figure 19. For information about the permanent display of the information view, refer to the OPUS/MENTOR manual.
ALPHA User Manual
Bruker Optik GmbH
Measurement
Chapt. 3
Peak picking result displayed in the spectrum window
Peak picking report Figure 19: Peak picking report
How to perform a single peak pick: Besides the Peak Picking command in the OPUS wizard, OPUS offers you also the possibility to pick specifically a single peak (i.e. to have the frequency value of a certain peak displayed) which is of interest to you. To do this, proceed as follows: 1
The spectrum in question is displayed in the spectrum window. Click with the right mouse button on the spectrum window and select in the context menu the Single Peak Pick command (see figure 20).
Figure 20: Single peak pick - Step 1
Bruker Optik GmbH
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Chapt. 3
Quick User Guide
2 3
As a result, the cursor changes its appearance as follows: Place the cursor on the peak which is of special interest to you and press the left mouse button. Thereupon, the frequency value of the peak in question is displayed above the peak (see figure 21). You can repeat a single peak pick as often as you like. Position of an individually selected peak
Figure 21: Single peak pick - Step 2
3.1.5
Defining the next procedures
After OPUS has performed a spectrum manipulation, the wizard switches automatically to the Evaluate level. Depending on your particular analytical task (quality control, substance identification quantitative analysis etc.) you can now evaluate your sample spectrum using the corresponding OPUS evaluation command. The following sections 3.2, 3.3 and 3.4 provide a detailed description of the most relevant evaluation commands (Quick Compare, Spectrum Search and Quantitative Analysis). For information about all available evaluation commands refer to the OPUS/MENTOR manual. After OPUS has performed an evaluation (e.g. Spectrum Search) the wizard switches automatically to the Report level. On this level, you decide how to deal with the current spectrum file. OPUS offers the following options: • • • •
saving the processed spectrum and/or printing the processed spectrum and/or unloading the spectrum file and/or measuring the next sample.
To do this, activate the corresponding checkbox(es) and click on the Go button. As a result, OPUS performs automatically the selected action(s). See figure 22.
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Chapt. 3
Figure 22: OPUS Wizard - Report level
How to save a processed spectrum: 1 2
Activate the Save Changes checkbox. Click on the Go button. As a result, OPUS saves the processed spectrum with the same file name and under the same path as the original spectrum, i.e. the original spectrum is overwritten by the processed one.
Note: If you want to preserve the original spectrum select the Save File As command in the OPUS File menu and define a different file name and/or path for saving the processed spectrum.
How to print a spectrum: 1 2
Activate the Print checkbox. Click on the Go button. As a result, the spectrum currently displayed in the spectrum window is printed.
How to unload a spectrum file: 1
Activate the Unload checkbox.
Note: If you want to unload a processed spectrum, it is advisable also to save it. To do this, also activate the Save Changes checkbox. (See section How to save a processed spectrum.)
2
Click on the Go button. As a result, the current spectrum file is unloaded from the OPUS browser.
H o w t o s ta r t t h e n e x t s a m p l e m e a s u r e m e n t : 1
Activate the Measure Next Sample checkbox.
Note: If you want to measure the next sample after having processed a spectrum it is advisable to save this spectrum. To do this, also activate the Save Changes checkbox. (See section How to save a processed spectrum.)
2
Click on the Go button. As a result, the Measurement dialog window (figure 10) opens again allowing you to start the next sample measurement by clicking on the corresponding button (see section 3.1.2.)
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Quick User Guide
3.2
Quality Control
3.2.1
General Information
The Quick Compare evaluation command allows to check whether the delivered goods or the self-made products are consistent with the specified quality criteria. For realizing this task, there are the following two OPUS commands: • Quick Compare Setup - This command allows to setup a quick compare method. The method setup has to be done prior to the actual Quick Compare. • Quick Compare - This command allows to perform a Quick Compare using the method you have set up in advance. (Quick Compare implies the comparison of a sample spectrum with one or several reference spectra.)
3.2.2
The general course of quality control
Generally, quality control can be subdivided into the following steps: 1 2 3 4 5
Measuring reference sample(s) and storing the spectrum (spectra) Setting up a quick compare method and saving method file Measuring the sample to be analyzed Performing a quick compare Interpreting the quick compare result
How to choose and measure a reference sample: For setting up a quick compare method, you first need to measure at least one or more reference spectra. In this case, reference spectra are spectra of samples of which you know for certain that they are absolutely consistent with the specified quality criteria. These samples are also called reference standards. When choosing and measuring reference sample(s), pay attention to the following aspects: • Use only pure samples as reference standard (i.e. samples that are free of unwanted contaminants). • Prepare the reference standards carefully (see chapter 4, Sample Preparation). • Avoid measurement errors (e.g. the ATR crystal is not completely covered with the sample). For detailed information about how to perform a measurement refer to section 3.1. 24
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H o w t o s e t u p a n e w Q u i c k C o m pa r e m e t h o d : 1
Click on the Evaluate tab and then on the Quick Compare button in the OPUS wizard. Thereupon, the following OPUS message appears:
Figure 23: OPUS Message
Note: This message appears only when you click on the Quick Compare button for the very first time because at this stage a quick compare method has not yet be set up. Otherwise, the quick compare method set up or loaded at last is used automatically.
2
Click on the OK button. Thereupon, the Quick Compare Setup dialog window opens. See figure 24.
Click on this button if you want to modify an existing method file (*.QCM). If you want to set up a new method, click on the other two tabs (fig. 25 and 26) and enter the desired parameter values. Then, return to this page of the dialog window and click on the Store Method button. Note: In the upper part of this page, an overview of the parameter values you have specified on the other pages of this dialog window is shown.
Figure 24: Quick Compare Setup - Load/Store Method
3
Click on the Reference Files tab and select reference spectrum file(s) in question (see figure 25).
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On this page, you select the reference spectrum/reference spectra for Quick Compare. You can select either: - only one reference spectrum or - all reference spectra that are stored in a certain directory (In this case, the reference spectra can originate from the different sample materials.) or - the average spectrum of all reference spectra stored in a certain directory. (In this case, the reference spectra must originate from the same sample material!)
Figure 25: Quick Compare Setup - Reference Files
4
Click on the Parameters tab and enter the desired parameter values (see figure 26). The entry of a comment is optional. When defining the frequency region for the quick compare, you can either: - use the file limits or, - enter the values for one or more regions manually or - select one or more frequency regions interactively. (See fig. 27.)
The threshold value has an influence on the quick compare result.a) You can either set this value (in %) using the slider or enter it manually. Figure 26: Quick Compare Setup - Parameters
a) With the threshold value, you determine the degree of similarity between the reference spectrum and the sample spectrum. In other words, you determine how similar reference spectrum and sample spectrum need to be in order that the quick compare result is OK. As a general guideline: The higher the threshold value is the higher the similarity between the reference and the sample spectrum needs to be in order to get an OK result.
If required, you can also define a data preprocessing method (first or second derivative) and you can exclude those spectral regions from the Quick Compare in which CO2 bands occur (between 2400 ... 2275 and 680 ... 660cm-1) by activating the corresponding checkbox. 26
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We recommend the interactive selection of the frequency region. Select those regions in which are the most relevant spectral information of the substance to be analyzed. To define further regions, click with the right mouse button on the Select Frequency Region(s) dialog and select the option Add Regions in the popup menu (see figure 27). Then, put the cursor on a boundary line of the newly added frequency region and move it with pressed left mouse button to the desired position. After having defined all relevant frequency regions, click on the OK button.
Figure 27: Interactive selection of the frequency region
5
To store the newly set-up method, click again on the Load/Store Method tab an then on the Store Method button. See figure 24.
For detailed information about this dialog window refer to the OPUS/MENTOR manual.
H o w t o p e r f o r m Q u i c k C o m pa r e : 1
2 3
4
Measure the sample of which you want to test the quality and manipulate the sample spectrum, if required. See section 3.1. (Do not unload the spectrum yet!) Click on the Evaluate level in the OPUS wizard. Click on the Quick Compare button. As a result, OPUS performs automatically a Quick Compare using the method you have set up before or the method which has been loaded last. Immediately after OPUS has executed a Quick Compare evaluation, the result is displayed automatically. (See figure 29, for example.)
Note: Alternatively, you can start a quick compare evaluation using the Quick Compare dialog window. To do this, click on the Evaluate level in the OPUS wizard. Then, click with the left mouse button next to the Quick Compare button and select the option Select "Quick Compare" method.... Thereupon, the Quick Compare dialog window opens (see figure 28). Bruker Optik GmbH
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Spectrum file of the sample to be analyzed (path and file name) Path and file name of the currently loaded method Note: Normally, it is the method you have set up or used at last.
Click on this button if you want to use a different method. You can decide whether the result is to be displayed immediately after the execution of the Quick Compare and/or printed automatically by activating the corresponding checkbox(es). Figure 28: Starting a Quick Compare
H o w t o i n t e r p r e t a Q u i c k C o m pa r e r e s u l t : The Quick Compare result is OK if the correlation value is higher than the threshold value you have determined. Analogous to this, the Quick Compare result is not OK if the correlation value is lower than the threshold value. In case of a Quick Compare evaluation, the correlation coefficient1 r is a measure for the similarity between the two items "reference spectrum" and "sample spectrum". Depending on what you have selected as reference for the Quick Compare (a single reference spectrum, an average spectrum or all spectra of a certain directory), keep in mind the following when interpreting the result: • If you have selected a single file or an average as reference, you will get either an OK or Not OK as result (see figure 29, 30 and 31). In both cases, the displayed result allows you to see at first sight whether the analyzed sample meets the specified quality criteria or not (see figure 29 and 30). • If you have selected all spectrum files of a certain directory as reference, you will not get a simply OK or Not OK as result. In this case, only those reference spectra which have a sufficient similarity with the sample spectrum, due to the threshold value you have entered and the correlation value OPUS has calculated, are displayed black. All other reference spectra which do not show a sufficient similarity with your sample spectrum are displayed gray (see figure 32)1. Normally, the correlation coefficient values can range from -1,0 (i.e. no similarity between the reference spectrum and sample spectrum at all) to +1,0 (i.e. absolutely identical spectra). For the quick compare result, this value is converted into percentage with the range –1 r 0 being mapped to 0% and the range 0 r 1 being mapped linearly to 0% ... 100%. 28
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Figure 29: Result of a Quick Compare using one Reference - Sample Spectrum is OK
Figure 30: Result of a Quick Compare using one Reference - Sample Spectrum is not OK
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Figure 31: Result of a Quick Compare using an average as reference - Sample spectrum is OK
Figure 32: Result of a Quick Compare using several references - 1 hit has been found
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Identification of an unknown Substance
3.3
Chapt. 3
Identification of an unknown Substa nce
3.3.1
General Information
The Spectrum Search evaluation command allows to identify an unknown substance on the basis of its IR spectrum by comparing this spectrum with the spectra of a library. Those library spectra which show an obvious similarity with the spectrum of the unknown substance are listed in a search report. As already mentioned, a spectrum search is only possible if at least one spectra library is available. By default, the two non-commercial spectra libraries (with 350 and 200 entries, respectively) are delivered together with the OPUS programme (see figure 33). Both libraries contain spectra of a number of classes of substances (e.g. polymers, pharmaceuticals etc.).
Figure 33: Available spectra libraries
Note: Besides the two libraries delivered with the OPUS software, Bruker also offers a number of additional spectra libraries which you can purchase.
A decisive factor for a successful substance identification is the appropriateness of the available spectra libraries, i.e. a spectrum search can yield only acceptable results if the selected library (libraries) contain(s) entries (i.e. spectra plus additional information) of the classes of substances (e.g. polymers, pharmaceuticals etc.) that you actually analyze.
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Quick User Guide
In addition, OPUS offers you also the possibility to create your own spectra library which is adapted to your special needs regarding the substances you intend to identify. See section 3.3.3 Creating, building up and maintaining your own spectra library.
3.3.2
T h e g e n e r a l c o u r s e o f a s u b s ta n c e i d e n tification
Generally, a spectrum search in a library can be subdivided into the following steps: 1 2 3
Measuring the sample of an unknown manipulating the sample spectrum, if required. Starting the spectrum search. Interpreting the result of a spectrum search.
substance
and
How to perform a spectrum search in a library: • Measure the sample of an unknown substance and manipulate the sample spectrum, if required (see section 3.1). • After having executed a manipulation command, OPUS switches to the Evaluate level. In case you did not manipulate the spectrum, click on the Evaluate tab in the OPUS wizard. • Click on the Spectrum Search button. Thereupon, OPUS starts the spectrum search using the factory-set search parameters. In this case, all spectra libraries that are in the directory OPUS path/Data/Library are searched. Note: OPUS offers you also the possibility to change the factory-set search parameters and/or to select different libraries. For detailed information about this topic refer to the OPUS/MENTOR manual.
• Immediately after OPUS has completed the spectrum search, the search report is shown (see figure 34).
How to interpret a spectrum search result: The search report consists of 4 sub-windows (see figure 34). The lower sub-window shows the list of all hits found in the selected library (libraries). By default, the first hit in the hit list is marked and its information (spectrum, structural formula and compound information, e.g. compound name, molecular formula, molecular weight etc.) are displayed in the upper three sub-windows. To see this kind of information for another hit, click in the hit list of the hit of which you want to see more information.
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Chapt. 3
Substance information
Structural formula
Library spectrum and query spectrum
Hit quality value
Hit list
Figure 34: Spectrum Search report
• The hit quality value in the hit list gives you a general clue to what extent the spectrum of the unknown substance (also called query spectrum) resembles the library spectrum. • The hit quality value can range from 0 (i.e. no resemblance at all) to 1000 (i.e. absolute conformity of the library spectrum with the query spectrum). The hit list is sorted according the hit quality value, i.e. the hit with the highest quality value ranks first in the hit list. • Moreover, you can compare visually the query spectrum with the library spectrum to find out whether there is a certain resemblance between the two spectra.
3.3.3
C r e a t i n g , b u i l d i n g u p a n d m a i n ta i n i n g your own spectra library
Besides the usage of the delivered and/or commercial spectra libraries, OPUS offers you the possibility to create your own library that suits your specific analytical needs. For creating, building up and maintaining your own spectra library, the following OPUS commands are available: • • • •
Initialize Library Store Spectrum in Library Library Editor Library Browser
For detailed information about these commands refer to the OPUS/ MENTOR manual.
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Quick User Guide
When creating your own spectra library, pay attention to following aspects: • When choosing the samples for the library, try to cover the hole range of the class(es) of substances you want to analyze with this library in the future. Keep in mind the following: The more extensive and diverse the library is, the better the search result will be. • Use only pure substances (i.e. substance that are free of unwanted contaminants). • Prepare these samples carefully (see chapter 4, Sample Preparation.) • Avoid measurement errors (e.g. the ATR crystal is not covered completely with the sample). • Before adding the measured sample spectra to the library, optimize them adequately using the available manipulation commands. • Add preferably absorption spectra1 to the library. • Think already in advance of the additional information you want to include in the library and make sure that they are available. The above mentioned aspects are crucial preconditions for the creation of a library that is to yield acceptable search results for future analyses.
1. In an IR spectrum, the position and intensity of the absorption bands are very substance-specific. Similar to a human fingerprint, the absorption spectrum of a substance is well-suited for the identification of it. 34
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Quantitation of a Sample Component
3.4
Chapt. 3
Quantitation of a Sample Component
3.4.1
General Information
If your sample is a mixture of several components (e.g. a tablet containing several active agents) OPUS allows you to quantitate one of these components which is of special interest to you (e.g. the quantity of active agent A contained in the tablet). For realizing this task, there are the following two OPUS commands: • Quant Builder - for setting up a QUANT method and • Quantitative Analysis - for performing the actual quantitative analysis When you perform a quantitative analysis, it is highly recommended that you normalize all spectra (i.e. both the calibration spectra and the spectra of the sample(s) you intend to analyze) before the evaluation. Spectra normalization is an OPUS manipulation command. Normalizing means that the spectra are scaled to that effect that the minimum and/or maximum of the spectra assume the same value. In doing so, the spectra can better be compared with each other. Especially in case of ATR spectra, a normalization is highly recommended. For detailed information about this command refer to the OPUS/MENTOR manual.
3.4.2
T h e g e n e r a l c o u r s e o f a q u a n t i ta t i v e analysis
Generally, a quantitative analysis can be subdivided into the following steps: 1
2 3
4
Getting a set of about 5 samples and determining the exact concentration values of the sample component in question using a different technique (e.g. weighing). These samples are also called calibration samples. They are required for setting up the QUANT method. Setting up a QUANT method using the OPUS command Quant builder and the calibration samples. Performing a quantitative analysis using the QUANT method you have set up before and the OPUS command Quantitative Analysis. Interpreting the analysis.
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Quick User Guide
W h e n c h o o s i n g t h e c a l i b r a t i o n s a m p l e s , pa y a t t e n t i o n t o t h e f o l l o w i n g a s p e c ts : • Ideally, the calibration sample set should contain at least 5 samples. • Make sure that the concentration value of the component in question differs from calibration sample to calibration sample.
How to setup a QUANT method: 1
2
3 4
5
Measure one of the calibration samples and manipulate the sample spectrum, if required (see section 3.1). Keep the spectrum file loaded in the OPUS browser. Click on the Evaluate tab in the OPUS wizard, select the option Quant Builder in the drop-down list and click on the Go button. Thereupon, the Quant Builder - New dialog window opens (see figure 35). The dialog window already includes the path and the file name of the currently loaded spectrum file. Enter the name of the component to be analyzed. Specify the unit of the measurement (e.g. mg, ml, %) for the concentration value. Note: The unit of measurement you enter in this dialog depends on the unit in which you have determined the concentration values of the calibration sample before. And the result of the quantitative analysis is displayed in this unit as well. Enter the exact component concentration value for the calibration sample in question. Note: You need to have determined this value before using a different analytical technique. Enter the exact concentration value of the component in question.
Path and file name of the current spectrum file
Note: This value needs to be determined before by a different techCalibration line nique.
Enter the component name
Enter the unit of measurement
Figure 35: Dialog Window Quant Builder
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Quantitation of a Sample Component
Chapt. 3
Already at this stage (i.e. on the basis of one calibration spectrum and its corresponding concentration value), OPUS calculates a calibration line1 (see figure 35). In the further course of the QUANT method setup, this calibration line will be improved by adding the data of the other calibration samples. Note: When you add the first calibration spectrum to a new QUANT method, make sure that the New option button is activated.
6
Click on the Set Integration Area button. Thereupon, the window shown in figure 36 appears allowing you to set an integration area and select an integration method.
Note: Set the integration area in such a way that the spectral band resulting from the component in question is within integration area. For this reason, it is recommended to set the integration area not until at least 3 or 4 calibration spectra have been added to the QUANT method because only at this stage you can recognize clearly the spectral band resulting from the component in question (see figure 37).
Spectral band resulting from agent A Note: You can change the integration area boundaries interactively by placing the cursor on a boundary and shifting it with pressed left mouse button.
Figure 36: Defining the Integration Area and the Integration Method
7
Now click on the Go to Quant button in order to return to the Quant Builder dialog window. 8 Click on the Save button. As you are setting up a new QUANT method, OPUS prompts you to enter file name and path under which the method file is to be saved. Enter a file name, specify the path and click on the Save button. 9 Thereupon, the Quant Builder dialog window disappears. 10 Measure the next calibration sample by clicking on the Measure Next Sample... button in the OPUS wizard (see section 3.1). 1.The calibration line visualizes the relation between the calibration spectra and the corresponding concentration values of the component in question. For the quantitation of a certain component, OPUS calculates the quantity of this component on the basis of the spectrum of the sample to be analyzed and the calibration line. Bruker Optik GmbH
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11 Open the Quant Builder dialog again by clicking in the OPUS wizard on the Evaluate tab, selecting in the drop-down list the option Quant Builder and clicking on the Go button. 12 Enter the component concentration value of the calibration sample in question. Note: For the second and every following calibration sample, you do not need to enter component name and unit again.
13 When adding the second or any further calibration spectrum to the existing QUANT method, make sure that the Add spectrum option button is activated. 14 To add the data of the second calibration sample to the QUANT method, click on the Save button. Thereupon, the Quant Builder dialog window disappears. 15 Repeat step 10 to 14 for the remaining calibration samples. Only after you have added 3 or 4 calibration spectra to the QUANT method is it recommended to set the integration area. To do this, activate the Change option button and click on the Set Integration Area button. Thereupon, the window shown in figure 37 appears.
Figure 37: Defining the integration area on the basis of several calibration spectra
At this stage, the window includes all calibration spectra added to the QUANT method so far. The display of several calibration spectra enables you to set the integration area because now the band resulting from the component to be quantified is clearly recognizable due to differences in the band height because the band height is quantitydependent. For detailed information about the Quant Builder command refer to the OPUS/MENTOR manual.
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Quantitation of a Sample Component
Chapt. 3
H o w t o p e r f o r m a q u a n t i ta t i v e a n a l y s i s : 1
2
Measure a sample of which you want to quantitate a certain component. For information about how to perform a measurement refer to section 3.1. Click on the Evaluate tab an then on the Quantitative Analysis button in the OPUS wizard. Thereupon, the Quantitative Analysis dialog window opens. See figure 38.
Spectrum file of the sample to be analyzed (path and file name) Path and file name of the currently loaded QUANT method Note: Normally, it is the method you have set up or used at last.
Click on this button if you want to use a different QUANT method.
Figure 38: Quantitative Analysis dialog
3 4
The sample spectrum file is already included in the File(s) for Quantitative Analysis field. The QUANT method you have set up or used at last is already loaded. In case you want to use a different method click on the Load Quant Method button and select the QUANT method file (*.q1) you intend to use.
Note: You can perform a quantitative analysis using either: • • • •
5
a newly set-up method or an existing method you have modified or an existing method you select explicitly or the method which has been loaded last.
Make sure that the Show results immediately button is activated (see figure 38). In this case, the result is shown immediately after OPUS has completed the evaluation. The result is displayed in form of a report (see figure 39).
Note: In case this check box has not been activated double-click on the QUANT data block of the spectrum file in order to display the quantitative analysis result.
6
Finally, click on the Analyze button.
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H o w t o i n t e r p r e t a q u a nt i ta t i v e a n a l y s i s r e s u l t :
Figure 39: QUANT Report - Result of a quantitative analysis
The QUANT report delivers the following information: • name of the component that has been quantitated • concentration value (prediction) of the component in question calculated by OPUS • standard deviation (sigma1) of the calculated prediction value • unit in which the calculated concentration value is given Note: You have specified this unit when setting up the QUANT method.
• the integration result for the spectral band which results from the component to be quantitated.
1. Sigma is the standard deviation of the calculated concentration value. The sigma value is determined by the quality of the QUANT method you have set up. Ideally, the sigma value should be as small as possible. 40
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Chapt. 4
4
S a m p l e P r e pa r a t i o n Proper sample preparation is crucial to obtain good and meaningful spectra. This chapter describes the most important sample preparation methods1. Useful information will give you some help in selecting the most suitable sample preparation method for a given sample.
How must the sam- homogeneous (constant concentration or composition within the ple be like? sample area to be analyzed) Disadvantages of a misleading or erroneous measuring data non-homogeneous sample What has to be • aggregation state of the sample considered when • absorptivity of the sample selecting a sample preparation method? • sample has to be very thin What has to be considered in case • sample has to be diluted by a solvent or powder that is not of a strongly strongly absorbing absorbing sample? (otherwise the spectrum is not meaningful) What kind of sol• Carbon tetrachloride vents can be used? • Carbon disulphide • Chloroform • Cyclohexane • Acetonitrile • Tetrachloroethylene
ALPHA allows to measure both solids and liquids. The most common sample preparation methods include: • No sample preparation (e.g. self-supporting film or measurement using an ATR unit) • Preparing a KBr pellet (for solids) • Preparing thin film of liquid sample solution between two transparent plates (for liquids) Caution: Most of the described sample preparation methods involve the use of hygroscopic materials (such as NaCl or KBr). If these materials come in contact with water or alcoholic solvents, they begin to dissolve or become cloudy and thus, impair the measurement results. Therefore, avoid all sources of water and even alcohol (ethanol and methanol). 1. For more detailed information about the different sample preparation methods refer to the relevant specialist literature. Bruker Optik GmbH
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Sample Preparation
4.1
Type of sample
films and polymers (with a thickness of less than approx. 100µm)
Advantage
enables fast sample measurements
Disadvantage
sometimes the samples are too thick
Tip
A large number of solid and liquid samples can also be analyzed by using an ATR unit. In this case a sample preparation is not required either.
4.2
42
N o Sample Preparation
K Br Pellet
Type of sample
solids
Advantages
• meaningful IR spectrum • KBr shows no absorption in the wavenumber area 4000cm-1 to 250cm-1 • this prevents the sample spectrum from containing any disturbing absorption bands
Disadvantages
• time-consuming sample preparation method • interference of water bands (3,960 to 3,480cm-1 and 1,950 to 1,300cm-1 and below 500cm-1) • in same cases there may be structural changes caused by high pressure applied to the KBr/sample mixture
What has to be considered during sample preparation?
• grind the sample as fine as possible to minimize the infrared light scattering on the particle surface, and the portion of the reflected light • keep everything moisture free as the KBr material is hygroscopic, otherwise the pellets become cloudy • it would be best to keep the KBr material in a drying oven at a temperature of 50 to 60°C
Tip
A common mistake is to use too much sample material. The concentration of the sample in KBr should be between 0.2% and 1% (i.e. typically a mixing ratio of 300:1).
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Thin film between two plates
4.3
Chapt. 4
Thin film between two plates
Type of sample
liquids (e.g. oils)
Advantages
• easy sample preparation method • small amount of sample material required
Disadvantages
• not suitable for samples which include water • the material of the plates (NaCl or KBr) are extremely moisture sensitive • frequently there are air bubbles between the plates
What has to be considered during sample preparation?
• pipette one drop of the sample on one of the plates • to avoid air bubbles the liquid sample between the two plates has to be a uniform film
Tips
• do not use the plates in case of samples that contain water as the plate material (NaCl or KBr) is extremely moisture sensitive • keep the plates always dry (e.g. in an exicator) • clean the plates only by using chloroform or high purity acetone and polish them carefully after each use
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Chapt. 5
5
Tr a n s m i s s i o n M e a s u ring 5.1
General Information
To perform transmission measurements the ALPHA-T module is available, see chapter 5.2. More information on the principle of transmission measurements is provided in the glossary in appendix D.
M e a s u r i n g i n t r a n s m i s s i o n i s s u i t e d f o r t h e f o llowing samples: • Solids, in the form of powder as well (except for highly absorbing substances) • Liquids • Gases Depending on the sample material, sample preparation can be very complex in case of measuring in transmission mode, see chapter 4.
A d v a n ta g e s : • Almost all kinds of samples can be analyzed. • Measurement represents the entire sample.
D i s a d v a n ta g e s : • Depending on the sample material a complex and sometimes difficult sample preparation is required. A successful transmission measurement substantially depends on how carefully the sample has been prepared. • Depending on the sample preparation method required, measuring in transmission may sometimes destroy the sample. • Too much a sample quantity can cause total absorption. • Additional accessories (e.g. liquid and gas cells) are required.
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Chapt. 5
Transmission Measuring
5.2
A LPHA-T
The ALPHA-T measurement module is designed for measurements in transmission. This measurement module allows to spectroscopically analyze both solids, liquids as well as gases.
A
B C
Figure 40: ALPHA-T
Definition
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A
Sample compartment lid
B
Sample holder
C
Ports for the IR beam passing the sample compartment
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Positioning sample in the ALPHA-T sample compartment
5.3
Chapt. 5
Positioning sample in the ALPHA-T sample compartment
Depending on the type of sample used (solid, liquid or gas) you can position the sample into the ALPHA-T sample compartment by means of different measurement accessories: • sample holder supplied by default; especially suited for KBr pellets or a thin film between two IR-transparent plates • plastic film holder (optional) • liquid cell (optional) • gas cell (optional)
5.3.1
Sample Holder
By default, the sample holder is mounted in the middle of the sample compartment. On the left side of the sample holder there is a fixture to insert the sample.
Fixture
Sample holder
Figure 41: ALPHA-T - Sample compartment
5.3.2
Plastic Film Holder
The plastic film holder is put into the fixture of the sample holder (figure 41).
5.3.3
Liquid Cell
To spectroscopically analyze liquid samples optional liquid cells are available. The liquid cells are inserted into the sample holder (see chapter 5.3.1) supplied by default.
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Chapt. 5
Transmission Measuring
When analyzing the sample in a liquid cell observe the following: • Avoid any air bubbles when filling in the sample into the liquid cell. • Thoroughly empty and clean the liquid cell after each measurement. • Clean the liquid cell using an appropriate solvent. Note: The solvent to be used for cleaning depends on the window material of the cell. Do not use water for cleaning in case of KBr windows. Do not use acidic solvents for cleaning in case of ZnSe windows.
5.3.4
Gas Cell
To spectroscopically analyze gaseous samples optional gas cells are available. The gas cell (B in figure 42) is supplied with a special gas cell holder (A in figure 42). A
B
Figure 42: Delivery content in case of a gas cell
To insert the gas cell into the ALPHA-T sample compartment you first have to displace the sample holder in the sample compartment, see figure 43a and b.
Figure 43: a) Standard position of sample holder
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b) Right sample holder position (for gas cell)
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Positioning sample in the ALPHA-T sample compartment
Chapt. 5
To d i s p l a c e t h e s a m p l e h ol d e r i n t h e A L P H A - T s a m p l e c o m pa r t m e n t . . . 1 2 3
...you have to use the supplied TORX screw driver TX20. Lift up the sample compartment lid. Remove the detachable blue casing at the front side of the sample compartment, see figure 44.
TORX screw
Detachable casing
Figure 44: Removing the casing at the front of the sample compartment
4 5 6
Loosen the two TORX screws which fix the sample holder, see figure 44. Mount the sample holder into the right position, see figure 43b. Put the detachable blue casing to the front of the sample compartment again.
To i n s e r t t h e g a s c e l l i n t o t h e s a m p l e c o m pa r tment... 1 2
...put the special gas cell holder into the fixture of the sample holder, see figure 45a. Position the gas cell on the sample holder as shown in figure 45b.
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Transmission Measuring
Figure 45: a) Insert gas cell holder
5.4
b) Gas cell on sample holder
Measuring Sample
Use the OPUS software to measure the sample. Information on measuring the sample can be obtained from the Quick User Guide in chapter 3. For detailed information on the OPUS software refer to the OPUS/MENTOR manual. As OPUS automatically recognizes the measurement module you work with, the software can automatically load the right experiment file supplied (i.e. Trans.XPM in case of transmission measurement). Thus, you can immediately start to measure. The experiment file supplied includes the default parameters set by Bruker. These parameters allow to perform a transmission measurement. For information on how to set up measurement parameters refer to the OPUS/MENTOR manual. Note: Keep the sample compartment closed during measurement.
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Chapt. 6
6
AT R M e a s u r i n g 6.1
General Information
ATR is the abbreviation of Attenuated Total Reflection. To perform ATR measurements three different modules are available, see chapter 6.2. For more information on the principle of ATR measurements refer to the glossary in appendix D.
M e a s u r i n g i n AT R i s s u i t e d f o r t h e f o l l o w i n g sample type: • • • • • •
Liquid Powder Paste Gel and cream Polymer film Surface coating
A d v a n ta g e s : • Non-destructive analysis method, i.e. the sample has not to be destructed for analysis • No sample preparation required • Only a small number of sample quantity required • Suited for samples which are actually too thick or highly absorbing for transmission measurement • Due to the multiple reflection of the IR light, the sample absorbs more light than in case of transmission measurement
D i s a d v a n ta g e s : • Falsified measurement result due to possible contaminations caused by previous sample material, solvents or fingerprints. • In case of multi-layer materials only the first layer will be spectroscopically analyzed. • The quality of the measurement result substantially depends on the contact pressure between sample and ATR crystal during measurement.
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6.2 6.2.1
ATR Measurement Module Overview
To perform ATR measurements by using ALPHA, the following ATR modules are available: • ALPHA-E • ALPHA-P • ALPHA-P ‘High Pressure’ variant
Figure 46: a) ALPHA-E
b) ALPHA-P
c) ALPHA-P ’High Pressure’ variant
These modules differ from each other in the following technical features:
ATR-Module
Crystal material available
Actual sampling Moving pressure arm by surface on ATR crystal means of a
ALPHA-E
Ge, ZnSe
Ø 5mm
knob
ALPHA-P
Diamond, Ge
Diamond:2 x 2mm Ge: Ø 2mm
lever
ALPHA-P ’High Pressure’ option
Diamond
2 x 2mm
knob
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6.2.2
Chapt. 6
AT R C r y s ta l Ty p e s
The crystal types available have the following technical features:
Spectral range (cm-1)
Crystal type
To be used for
Diamond
all kinds of sample material, includ- covers the complete ing hard and sharp-edged samples spectral range specified for ALPHA, see appendix A
Ge (Germanium) samples with a high absorptivity, especially carbon-filled samples (e.g. O-rings, polymer) ZnSe (Zinc Selenide) CAUTION TOXIC!
5,000 - 550
all kinds of sample material, except >500 for acids (pH -value <5) and bases (pH-value >8) and sharp-edged samples
Refraction index n = 2.43
n = 4.01
n = 2.43
Caution: Zinc selenide is a toxic material. During normal spectrometer operation the material does not pose a health risk. Be careful, however, if the crystal is broken. Avoid generating dust. The dust is harmful by inhalation, ingestion or skin absorption.
6.2.3
E x c h a n g i n g AT R C r y s ta l P l a t e
The ATR crystal plates can include one of the following crystal material: ZnSe, Ge and diamond. The color of the crystal indicates which crystal material is used.
Crystal material
Crystal color
Diamond
transparent
Ge (Germanium)
silver-gray
ZnSe (Zinc selenide)
yellow
It is not easy to rotate the crystal plate manually. Therefore, it is recommended to use the stick supplied. The leverage effect of the stick facilitates rotating the crystal plate.
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1
Put the stick into the bore of the crystal plate, see figure 47.
Rotating counterclockwise releases the crystal plate
Rotating clockwise locks the crystal plate Figure 47: Exchanging crystal plate
2 3 4 5 6
Rotate the crystal plate counterclockwise by means of the pin as far as it will go (approx. 20°). Remove the crystal plate. Place the new plate onto the ATR measurement module and put the pin into bore of the crystal plate. The stick helps to tighten the crystal plate again, by rotating the plate clockwise as far as it will go. Remove the pin from the crystal plate bore.
6.2.4
Moving Pressure Application Device
Depending on the measurement module used the pressure application device can be moved in different ways.
ALPHA-E The pressure application device is moved upwards or downwards by means of a knob (figure 48): • upwards - you have to rotate the knob counterclockwise • downwards - you have to rotate the knob clockwise The inner part of the pressure arm is equipped with a slip-clutch mechanism which is activated as soon as the optimal contact pressure between sample and anvil has been applied. Further rotating the knob, which is only possible by substantial force, would not have any effect on the contact pressure already applied. 54
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However, the contact pressure actually applied (i.e. how much the anvil presses the sample against the ATR crystal) depends on how far you rotate the pressure arm down.
Knob
Pressure arm Anvil
Figure 48: ALPHA-E - Pressure application device
You can swing away the pressure arm and the anvil from the sampling surface. The pressure arm is rotatable by 360°. If you swing the pressure arm towards the sampling surface again, it snaps into place exactly above the ATR crystal.
ALPHA-P The pressure application device is moved upwards or downwards by means of a lever (figure 49). • lever in back position - moves the anvil up • lever in front position - moves the anvil down Lever to move the anvil Height adjusting knob to move the complete pressure application device Red control spot indicates optimal contact pressure Anvil
Figure 49: ALPHA-P - Pressure application device
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The optimal contact pressure applied on the sample is ensured if the red control spot (figure 50) is exactly in the middle of the round recess.
The red spot in the middle of the round recess indicates an optimal contact pressure applied on the sample.
Figure 50: ALPHA-P - Indication of the optimal contact pressure
To a d j u s t t h e h e i g h t o f t h e c o m p l e t e p r e s s u r e application device is required if... 1
2
56
...the lever is right in the front position but the anvil has not any contact with the sample. In this case use the height adjusting knob (see figure 51) and move the complete pressure application device downwards until the red control spot is exactly in the middle of the round recess. You cannot move the lever right to the front position as the sample is too thick. In this case use the height adjusting knob (see figure 51) and move the complete pressure application device upwards, until the lever can be moved right to the front position and the red control spot is exactly in the middle of the round recess.
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Chapt. 6
Turning the height adjusting knob to the right, moves the complete pressure application device downwards. Turning the height adjusting knob to the left, moves the complete pressure application device upwards.
Figure 51: ALPHA-P - Height adjustment knob
You can swing away the pressure application device from the sampling surface. The pressure application device is rotatable by 360°. If you swing the pressure application device towards the sampling surface again, it snaps into place exactly above the ATR crystal. Note: For ALPHA-P as ’High-Pressure’ option refer to ALPHA-E.
6.3
Performing Cleanness Te st
Before you start measuring perform a cleanness test by means of the OPUS software. This kind of test is a reference measurement of the ATR crystal and defines the maximum allowed limit of the crystal contamination. For further details refer to the OPUS/MENTOR manual.
6.4
Placing Sample on ATR Crystal 1 2
Make sure that the sampling surface, ATR crystal and anvil are clean, see chapter 6.6. Place the sample on the middle of the sampling surface. Use a small amount of sample, only enough to cover the ATR crystal.
Caution: When using flammable and/or explosive materials, always wear eye protection and use a very small amount of the material. In case of extremely volatile materials do not inhale the vapor and observe the safety requirements.
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Note: If the sample cannot be placed onto the ATR crystal as the distance between the ATR crystal and anvil is too small, move the pressure application device upwards (see chapter 6.2.4).
3
4 5
Press the anvil against the sample (see chapter 6.2.4). Make sure that the optimum contact pressure is used to press the sample against the ATR crystal. Acquire a sample spectrum (see chapter 6.5). For detailed information to perform a measurement refer to chapter 3. Move the pressure application device up again and remove the sample.
Note: Samples should not be left in contact with the crystal for an extended period of time as some samples may degrade the crystal material, and discoloration of the metal plate may occur. Once the measurement has been made, remove the sample from the crystal.
6
6.5
Thoroughly clean the sampling surface, ATR crystal and anvil (see chapter 6.6).
M easuring Sample
Use the OPUS software to measure the sample. Information on measuring the sample can be obtained from the Quick User Guide in chapter 3. For detailed information on the OPUS software refer to the OPUS/MENTOR manual. As OPUS automatically recognizes the measurement module and the ATR crystal you work with, the software can automatically load the right experiment file supplied. Thus, you can immediately start to measure. Depending on the ATR crystal used, the following experiment files are supplied: • ATR_Di.XPM • ATR_Ge.XPM • ATR_ZnSE.XPM The experiment files supplied include the default parameters set by Bruker. These parameters allow to perform an ATR measurement. For information on how to set up measurement parameters refer to the OPUS/MENTOR manual.
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Cleaning ATR Module
6.6
Chapt. 6
C leaning ATR Module
When performing one measurement after the other it is important to clean all remains of the previous sample from the sampling surface and crystal, as well as from the anvil. Otherwise, you may get falsified measurement results.
C l e a n i n g s o l v e n ts : • Alcohol • Acetone Note: When using solvents inspect the materials safety data sheets associated with the solvents you are using and observe any recommended handling procedure.
The solvent used for cleaning depends on the sample that has been analyzed. In all cases it is best to try to clean the sampling surface by the mildest solvent possible.
Before cleaning... • ...swing away the pressure application device from the sampling surface.
When cleaning... • • • •
...apply the solvent to the ATR sampling surface using a Q-tip. Gently remove the solvent using a Q-tip or lint-free cloth. Clean the anvil as well. Repeat the cleaning procedure until all sample remains have been removed. Caution: Never use caustic or abrasive substances or strong acids. These substances can damage the ATR sampling surface. Never rub with paper products as they may be abrasive and could cause scratches on the crystal surface, especially with Ge and ZnSe.
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6.7
ATR Sp ectra
• Similar to transmission spectra Intensities of the spectral features are of lower absorbance than the corresponding features in a transmission spectrum, especially, in the high wavenumber (short wavelength) region of the spectrum. • Intensity Is related to the penetration depth of the evanescent wave into the sample. This depth depends on the refractive index of the crystal and sample, and on the wavelength of the IR radiation. • Main benefit The relatively thin depth of penetration of the IR beam into the sample creates the main benefit of ATR sampling. This is in contrast to traditional FT-IR sampling by transmission where the sample must be diluted with IR transparent salt, pressed into a pellet or pressed to a thin film, prior to analysis to prevent totally absorbing IR bands.
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Chapt. 7
7
M a i n t e n a n c e & R e pa i r ALPHA is a low-maintenance instrument, i.e. the operator can replace components with a limited service life (e.g. IR source). The following maintenance procedures are described in this chapter: • • • • •
Replacing IR source Replacing desiccant Replacing windows Cleaning windows Cleaning spectrometer housing
General Instructions Perform only the maintenance procedures described in this manual. Strictly observe the relevant safety precautions. Any failure to do so may cause property damage or personal injury. In this particular case Bruker does not assume any liability. Maintenance or repair procedures not described in this manual should only be performed by a Bruker service engineer. For service assistance, see appendix E. Depending on the degree of hazard the safety instructions to be observed in case of spectrometer maintenance or repair are classified as follows: Caution
indicates that minor personal injury or property damage CAN result if proper precautions are not taken.
Note
draws your attention to particularly important information on the product, or to the product operation.
The safety instruction Caution is indicated by triangular warning label.
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Maintenance & Repair
7.1
Replacing IR Source
ALPHA is equipped with a highly-efficient, low-power, air-cooled infrared source.
When do you have to replace the IR source? The average IR source lifetime is specified with about 44.000 operating hours. Before this period has been expired the following message pops up in OPUS: End of average lifetime is nearly reached, spare part will be required. In this case the OPUS status light ( status light allows to continue measuring.
) is yellow. A yellow
Order a replacement source (order no: 1005855). As soon as you have received the replacement, the existing source should be replaced. Note: To allow the status light become green again, you have to click on the Ignore button in the Instrument Status Message dialog (see figure 65 on page 76). The End of average lifetime is nearly reached, spare part will be required message will be displayed in regular intervals.
If the source is defective, the OPUS status light becomes red. The following message pops up in OPUS: Source is broken. A red status light does not allow to continue measuring. The source must be replaced.
How do you have to replace the IR source?
1 2 3
4
62
Switch off the power plug. The source is accessible from the rear side of the spectrometer. Make sure that you have access to the rear side. Remove the cover plate at the rear side by loosening the 4 TORX screws (A in figure 52). To loosen the screws use the TORX TX20 screw driver supplied. Take off the cover plate.
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Replacing IR Source
Chapt. 7
A
Figure 52: ALPHA rear side - Removing cover plate
Note: During spectrometer operation the light source becomes very hot. Wait until the light source has cooled down sufficiently before you begin to replace it. In case of non-observance there is the risk of skin burn!
5 6
Loosen the two fixing screws of the IR source (see figure 53). Use the TORX TX20 screw driver supplied. Strip off the green source plug (see figure 53). There will be a beep.
IR source
Fixing screws of the source (TORX screws)
Source plug
Figure 53: ALPHA rear side - Removing source
7 8
Pull out the source from the spectrometer housing. Insert the new IR source into the spectrometer housing. Make sure that the alignment pin (A in figure 54) correctly fits in the alignment groove (B in figure 54).
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B A
Figure 54: ALPHA - Exact positioning of source
9 Fix the source by fastening the two TORX screws (see figure 53). 10 Put the green source plug into the SRC female connector. There will be a beep. 11 Attach the cover plate and fasten the 4 TORX screws again (see figure 52). 12 Connect the power plug to the mains socket again.
A ft e r r e p l a c i n g t h e I R s o u r c e . . . ...you have to perform an instrument test.
To p e r f o r m a n i n s t r u m e n t t e s t . . . 1 2 3
64
...click on the Instrument Test button on the OPUS wizard (see figure 55). The test starts and takes about 5 minutes. Wait until the test has finished. If the test has passed, the OPUS status light is green. If the instrument has failed, see chapter 8.
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Replacing Desiccant Bags
Chapt. 7
Figure 55: Starting instrument test by the OPUS wizard
Resetting source operating hour meter 1 2 3 4
7.2
Click on the OPUS status light ( ). The Instrument Status dialog opens. Click on the Source Icon. Another dialog opens. Click on the Reset button of this dialog. If the Reset button is deactivated, click on the Help button first.
Rep l aci n g D e s ic c a n t B a g s
Too high a humidity inside the spectrometer can be recognized by H2O bands in the spectrum. As the desiccant inside the spectrometer binds humidity, H2O bands in the spectrum can be reduced to a minimum. The air inside the complete ALPHA optics unit (measuring and optics compartment) is convectively kept dry using a desiccant which is enclosed in removable small bags.
When do you have to replace the desiccant bags? If the desiccant is saturated and cannot further absorb any humidity, it has to be replaced. In this case the Humidity out of range message is displayed in OPUS. Bruker Optik GmbH
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Maintenance & Repair
Besides, the OPUS status light ( ) becomes yellow. Order new desiccant (order no: 1000917). Measuring is still possible even if the status light is yellow. As soon as you have received the new desiccant bags, replace the old ones.
How do you have to replace the desiccant bags?
1 2 3
4
Switch off the power plug. The desiccant bags are accessible from the rear side of the spectrometer. Make sure that you have access to the rear side. Remove the cover plate at the rear side by loosening the 4 TORX screws (A in figure 56). To loosen the screws use the TORX TX20 screw driver supplied. Take off the cover plate. A
Figure 56: ALPHA rear side - Removing cover plate
5
66
Pull out the used desiccant bags. A pair of tweezers may be helpful.
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Replacing Windows
Chapt. 7
Desiccant bags
Figure 57: ALPHA rear side - Replacing desiccant bags
6
7
The replacement desiccant bags are protected by an extra packaging. Open this packaging and take out the desiccant bags. Note: Alternatively, you can place the spent bags into an oven at 130°C for at least 10 minutes. Completely insert the desiccant bags properly into the spectrometer as shown in figure 57.
Caution: Do not cut or tear off the bags into single pieces, nor ingest the desiccant.
8 9
7.3
Attach the cover plate and fasten the 4 TORX screws again (see figure 56). Connect the power plug to the mains socket again.
R eplacing Windows
The ALPHA basic module has two ports: one IR output and one IR input port (see figure 58). The IR beam enters the measurement module by the IR output port. Afterwards, the beam is directed to the basic module again via the IR input port. The ports are closed by means of exchangeable IR transparent windows. Note: By default, the spectrometer is equipped with KBr windows. In case of the ’High Humidity’ option the windows are made of ZnSe. Caution: Zinc selenide is a toxic material. During normal spectrometer operation the material does not pose a health risk. Be careful, however, if a window is broken. Avoid generating dust. The dust is harmful by inhalation, ingestion or skin absorption.
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Chapt. 7
Maintenance & Repair
Ports closed by KBr windows
Basic module
Exchangeable measurement module
Figure 58: Window position
When do you have to replace the windows? KBr is a hygroscopic window material which causes the spectrometer windows to become opaque in the course of time. Opaque windows substantially reduce infrared transmittance which can be indicated by a failed performance or instrument test. In this case you have to replace the windows. ZnSe windows, however, only need to be replaced when they are broken.
How to replace the windows? 1
2 3 4
5
6
68
Remove the basic module from the measurement module by pressing the lock on the basic module right down. Pull out the measurement module from the basic module, towards your direction (see chapter 2.6). To remove the windows use the assembly tool supplied. Insert the two pins of the assembly tool into the respective holes on the window frame (see figure 59). Rotate the tool several turns counterclockwise and pull out the tool including the window assembly (i.e. window and assembly frame). Insert the two pins of the assembly tool into the respective holes of the assembly frame on the new window. Put the window assembly into the hole of the basic module. To fasten the window assembly rotate the tool several turns clockwise.
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Replacing Windows
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Chapt. 7
Pull out the assembly tool from the holes on the assembly frame. After replacing the windows push the measurement module right against the basic module. Press the lock on the basic module again right down (see chapter 2.6).
Lock/release
Window assembly (window in assembly frame) Fitting tool to replace windows
Figure 59: Replacing windows
A ft e r r e p l a c i n g t h e w i n d o w s . . . ...you have to perform an instrument test.
To p e r f o r m a n i n s t r u m e n t t e s t . . . 1 2 3
...click on the Instrument Test button on the OPUS wizard (see figure 60). The test starts and takes about 5 minutes. Wait until the test has finished. If the test has passed, the OPUS status light is green. If the instrument has failed, see chapter 8.
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Maintenance & Repair
Figure 60: Starting instrument test by the OPUS wizard
7.4
C leaning Windows
Clean the windows by using a dry, lint-free cloth only. Caution: KBr windows are hygroscopic. Do NOT clean them by using water or solvents.
7.5
C leaning Spectrometer Housing
The outer spectrometer surface can be cleaned only by using a dry or damp cloth. Do not use detergents with organic solvents, acid or base! Caution: Do by no means clean the interior of the spectrometer. This may lead to serious spectrometer damage.
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Chapt. 8
8
Tr o u ble s h o o t i n g 8.1
G en era l In fo r m a tio n
This chapter describes only those spectrometer problems and their causes which you can solve by yourself. In all other cases contact the Bruker service. For service addresses and telephone numbers refer to appendix E. A spectrometer problem can be indicated as follows: • The status light at the spectrometer top side lights yellow or red or not at all. • The OPUS status light is yellow or red or gray. • The instrument test/performance test failed. (In this case, a test protocol is automatically displayed.) • Error messages in OPUS • Diagnostics LEDs at the spectrometer rear side These diagnostic means allow to find out the cause of a spectrometer problem and to solve it by yourself, or at least to narrow down the cause of the problem. If the solutions listed below do not solve the problem, contact Bruker service. For this case OPUS provides the possibility to send a complete spectrometer status report to the Bruker service for a remote fault diagnostics. To do this, proceed as follows: 1 2
Click on the OPUS status light. The status light is in lower right corner of the OPUS interface (see figure 62). The Instrument Status dialog window opens. Click on the Send Report button (see figure 63). The report is sent by e-mail to opusreports@brukeroptics.
Note: This function requires an e-mail program installed on your computer and a set-up mail account. In addition, your spectrometer needs to be connected to a network computer.
Alternatively, you can save the report on your computer by clicking on the Save Report button. The report is automatically saved under the following path: OPUS-Pfad\InstrReports\ .... The folder in question is named after the current date and time of the storage.
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Chapt. 8
Troubleshooting
8.2
Available Diagnostic Means
Sp e c t r o m e t e r Sta t u s I n d i c a t o r The status indicator is on the spectrometer top side.
A
Figure 61: ALPHA - Status Indicator
The spectrometer status indicator can have the following colors: green, yellow and red. These colors indicate the following spectrometer status: • Green (permanent): Spectrometer is in proper operating condition. • Green (flashing): Spectrometer is in the stand-by mode. • Yellow: Spectrometer is in the initialization phase or it indicates a warning (e.g. IR source has not yet reached its operating temperature, the air humidity content inside the spectrometer is too high etc.) • Red: Spectrometer malfunction, defective spectrometer component
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Available Diagnostic Means
Chapt. 8
O P U S Sta t u s L i g h t The status light is in the lower right corner of the OPUS interface.
Status light Figure 62: OPUS interface
The OPUS status light can have the following colors: green, yellow, red and gray. These colors indicate the following spectrometer status: • Green (permanent): Spectrometer is in proper operating condition. • Yellow: Spectrometer is in the initialization phase, or a warning is indicated (e.g. IR source has not yet reached its operating temperature, the validity period of the instrument is expired, the air humidity content inside the spectrometer is too high etc.) • Red: Spectrometer malfunction, defective spectrometer component, performance test / instrument test failed • Gray: In OPUS, no spectrometer is selected or the spectrometer is off or the spectrometer is in stand-by mode. Note: In case of a yellow status light measuring is still possible. If the status light is red or gray, measuring is not possible. The color of both status lights, in OPUS and on the spectrometer, corresponds in most cases except for one case: if the performance test or the instrument test has failed the OPUS status light is red whereas the spectrometer status indicator lights yellow.
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Chapt. 8
Troubleshooting
O P U S I n s t r u m e n t St a t u s D i a l o g Click on the OPUS status light (see figure 62). The Instrument Status dialog opens.
A
B
Figure 63: Optics Diagnostics - Instrument Status dialog
A The status of the hardware components, e.g. source, laser, interferometer etc. is displayed in the upper icon line. The status can be as follows: OK (green): Component is okay.
WARNING (yellow): The exact meaning of a warning depends on the component in question. In case of the source a warning means: • End of the specified component lifetime is nearly reached. In this case, measuring is still possible. • The source is still warming-up (duration: about 7 min.) In this case, measuring is not possible. ERROR (red): Component is defective. In this case measuring is not possible.
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Available Diagnostic Means
Chapt. 8
B The second row of icons refer to the possible active test channel and indicates the result of the last instrument test performed. The results can be as follows:
INACTIVE (yellow): The single tests of the particular test category are disabled.
PASSED (green): Instrument test passed. Test is still valid.
EXPIRED (light blue): Instrument test validity period has expired.
FAILED (red): Instrument test failed.
To p e r f o r m a f a u l t d i a g n o s i s o f a pa r t i c u l a r hardware component... 1 2
...click on the respective icon in the first row of the Instrument Status dialog. The Instrument Status Message dialog opens:
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Troubleshooting
Status indication (for the component in question) Error message (for the component in question)
Component in question
Figure 64: Instrument Status Message
When you click on the Service Info button the diagnostics page of the component in question opens. Figure 65 shows the diagnostics page of the source. These pages contain all relevant information about the current operating state of the respective spectrometer component. Note: You can send these diagnostics pages as full report to the Bruker service by e-mail allowing the technician a first remote fault diagnostics (see section 8.1).
Figure 65: Source Diagnostics Page
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Available Diagnostic Means
Chapt. 8
Error Messages in OPUS Error messages concerning the spectrometer can appear in OPUS as follows: • in the Instrument Status Message dialog (see figure 64). • in a yellow message bubble in the lower right corner of the OPUS interface (see figure 66a). • in a normal message window (see figure 66b).
Error Message
Figure 66: a) Information bubble
b) Message window
Note: In case of a spectrometer problem indicated by an error message, the status indicator on the spectrometer and the OPUS status light are yellow or red.
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Chapt. 8
Troubleshooting
Sp e c t r o m e t e r D i a g n o s t i c L E D s The diagnostic LEDs are at the spectrometer rear side.
ABC Figure 67: ALPHA rear side -Diagnostic LEDs
Type
Definition
A
TKD LED
The green TKD LED indicates that the interferometer mirror is within the data acquisition range. When data acquisition actually takes place the light intensity changes to bright green. The TKD abbreviation means Take Data.
B
ACC LED
The yellow ACC LED indicates that the network accesses the optics. During transition of measuring data the LED will be light yellow. The ACC abbreviation means Access.
C
DIR/ERR LED
In normal operation mode the DIR/ERR LED flashes slightly red and indicates the scanner movement. If the LED lights permanently bright red, there must be an interferometer problem, e.g. missing laser signal. As long as this LED lights permanently red no data acquisition is possible. The DIR abbreviation means Direction, ERR means Error.
P e r f o r m a n c e Te s t a n d I n s t r u m e n t Te s t Both tests check whether the spectrometer achieves the specified performance. But they differ as follows:
Performance Test
Instrument Test
The test procedure includes the following tests
• Signal-to-noise test • Deviation from 100% line
• Signal-to-noise test • Deviation from 100% line • Wavenumber accuracy test
Number of test measurements
1
11
Test duration
about 1 minute
about 5 minutes
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Problem - Possible Causes - Solutions
When is the test performed?
8.3
Chapt. 8
Performance Test
Instrument Test
• automatically after OPUS has been opened again • automatically after ALPHA has been accessed again • automatically after the measurement module or the ATR crystal plate has been substituted by another measurement module or another ATR crystal plate
• automatically when the PC and ALPHA communicate with each other for the very first time • automatically when you use a measurement module or an ATR crystal plate for the very first time • manually (i.e. you have to start the instrument test yourself) after the defined instrument test validity period has expired; Note: The factory-set validity period is 7 days.
Problem - Possible Causes Solutions
8.3.1
A P r o b l e m i n d i c a t e d b y t h e Sp e c t r o m e t e r Sta t u s I n d i c a t o r
The status indicator is on the spectrometer top side (see figure 61).
Sp e c t r o m e t e r s ta t u s i n d i c a t o r i s o f f Possible Cause
Solution
Spectrometer is not connected properly to the mains supply.
Check the power cord connection at both ports, the mains outlet and the POWER port at the spectrometer rear side. See ALPHA Installation Instructions, chapter 3.2.
No voltage is applied
Check whether the proper voltage is applied at the mains outlet to which the spectrometer is connected.
Short circuit in the mains adapter of power cable.
A short circuit is accompanied by a "ticking" sound in the mains adapter. Unplug the power cord immediately and contact Bruker service (see appendix E).
If the problem has a different cause... ...contact Bruker service (see appendix E).
Sp e c t r o m e t e r s ta t u s i n d i c a t o r i s y e l l o w Possible Cause
Solution
Spectrometer is still in the initialization Wait until the spectrometer initialization is completed. (duration: about 1 minute) phase. IR source has not yet reached its operating temperature. Note: In this case the following message appears: Device not ready.
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The warm-up takes about 7 minutes. As soon as the IR source has reached its operating temperature the status light will automatically turn green. Wait until the warm-up has been completed.
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Troubleshooting
Possible Cause
Solution
The end of the specified lifetime of the source is nearly reached. Note: In this case the following message appears: End of average lifetime is nearly reached, spare will be required.
Order a spare source (part no. 1005855). After the receipt, replace the old source (see chapter 7 Repair and Maintenance, section 7.1). Note: Despite this message, measuring is still possible. To turn the OPUS status light green again click on the Ignore button in the Instrument Status Message dialog (figure 64). The message will be repeated in certain time intervals until you have replaced the source.
Performance test or instrument test failed.
For information about the solution of this problem refer to section 8.3.4 Performance Test failed or section 8.3.5 Instrument Test failed.
Instrument test validity period is expired. Note: In this case the following message appears: An instrument test is required or one of the instrument components does not meet its specifications.
Click on the OPUS status light (figure 62). The Instrument Status dialog (figure 63) opens. The measurement channel of which the instrument test validity period is expired is labelled Expired. Start a new instrument test by clicking on the Instrument Test button in the OPUS wizard. Wait until the test is completed (duration: about 5 minutes).
Air humidity inside the spectrometer is Replace the desiccant bags (see chapter 7 Repair and too high. Note: In this case the folMaintenance, section 7.2). lowing message appears: Humidity out of range. Laser wavenumber needs to be recali- Click on the Calibrate button (figure 68) and wait until brated. Note: In this case a correthe calibration is completed. sponding message appears in the lower right corner of the OPUS interface. See fig. 68. If the problem has a different cause...
...contact the Bruker service (see appendix E).
Figure 68: OPUS message prompting an instrument calibration
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Problem - Possible Causes - Solutions
Chapt. 8
Sp e c t r o m e t e r s ta t u s i n d i c a t o r i s r e d Possible Cause
Solution
Defective spectrometer component
To find out which component is defective, click on the OPUS status light (figure 62). The Instrument Status dialog opens (figure 63). If the laser or the interferometer or the electronics or the automation or the detector is defective, contact Bruker service. In case of a defective source, replace the old source as described in chapter 7 Maintenance and Repair, section 7.1.
No measurement module is placed in the basic module or the measurement module is not locked properly in place. In case of the ATR-module: No ATRcrystal plate is installed, or the plate is not installed properly.
Place the measurement module into the basic module and lock it properly in position (see chapter 2, section 2.6). In case of an ATR-Module, install the ATRcrystal plate properly (see chapter 6, section 6.2.3).
If the problem has a different cause...
...contact Bruker service (see appendix E).
8.3.2
A P r o b l e m i n d i c a t e d b y t h e O P U S Sta t u s Light
The OPUS status light is in the lower right corner of the OPUS interface (see figure 62).
O P U S Sta t u s l i g h t i s y e l l o w Possible Cause
Solution
IR source has not yet reached its operating temperature. Note: In this case the following message appears: Device not ready.
The warm-up takes about 7 minutes. As soon as the IR source has reached its operating temperature the status light will automatically turn green. Wait until the warm-up is completed.
The end of the specified lifetime of the source is nearly reached. Note: In this case the following message appears: End of average lifetime is nearly reached, spare will be required.
Order a spare source (part no. 1005855). After the receipt, replace the old source (see chapter 7 Repair and Maintenance, section 7.1). Note: Despite this message measuring is still possible. To turn the OPUS status light green again click on the Ignore button in the Instrument Status Message dialog (figure 64). The message will be repeated in certain time intervals until you have replaced the source.
Instrument test validity period is expired. Note: In this case the following message appears: An instrument test is required or one of the instrument components does not meet its specifications.
Click on the OPUS status light (figure 62). The Instrument Status dialog (figure 63) opens. The measurement channel of which the instrument test validity period is expired is labelled Expired. Start a new instrument test by clicking on the Instrument Test button in the OPUS wizard. Wait until the test is completed (duration: about 5 minutes).
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Troubleshooting
Possible Cause
Solution
Air humidity inside the spectrometer is Replace the desiccant bags (see chapter 7 Repair and too high. Maintenance, section 7.2). Note: In this case the following message appears: Humidity out of range. Laser wavenumber needs to be recali- Click on the Calibrate button (figure 68) and wait until brated. the calibration is completed. Note: In this case a corresponding message appears in the lower right corner of the OPUS window. See figure 68. If the problem has a different cause...
...contact Bruker service (see appendix E).
O P U S s ta t u s l i g h t i s r e d Possible Cause
Solution
Performance test or instrument test failed.
For information about the solution of this problem refer to section 8.3.4 Performance Test failed or section 8.3.5 Instrument Test failed.
Defective spectrometer component
To find out which component is defective, click on the OPUS status light (figure 62). The Instrument Status dialog opens (figure 63). If the laser or the interferometer or the electronics or the automation or the detector is defective, contact Bruker service. In case of a defective source, replace it as described in chapter 7 Maintenance and Repair, section 7.1.
If the problem has a different cause...
...contact the Bruker service (see appendix E).
O P U S s ta t u s l i g h t i s g r a y Possible Cause
Solution
Spectrometer is still in the initialization Wait until the spectrometer initialization is completed. phase. (duration: about 1 minute) For other possible causes...
...refer to the above section 8.3.1 Spectrometer Status Lamp does not light.
The OPUS status light is gray while the spectrometer status light has one of the three possible colors. This state indicates a communication problem between ALPHA and the PC. This problem can be caused by:
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Problem - Possible Causes - Solutions
Chapt. 8
Possible Cause
Solution
The IP address of the ALPHA spectrometer is not selected in OPUS or the wrong IP address has been selected.
Enter the correct spectrometer IP address in OPUS. To do this, select in the OPUS Validation menu the Optic Setup and Service command. The Optic Setup and Service dialog opens. Select the Alpha option in the Configuration drop-down list and enter the spectrometer IP address (by default 10.10.0.1) into the field below (Optical Bench URL). See figure 69.
Spectrometer is not connected to the computer.
Connect the spectrometer to the computer using the supplied data cable (crossover, Cat-5). See Installation Instructions, chapter 3.
The spectrometer is connected to the PC using the wrong cable type.
Connect the spectrometer to the PC using only the supplied cross-over, Cat5-cable. See Installation Instructions, chapter 3.
The RJ45-plug(s) of the data cable has Check the data cable cord connection at both RJ45(have) not been connected properly. ports, the ETH/LAN port at the spectrometer rear side and the Network/LAN port of the PC. See Installation Instructions, section 3.2. The factory-set standard IP address of Reassign the standard IP address to the spectrometer the spectrometer (10.10.0.1) has been using the DIP-switch at the spectrometer rear side. See changed. Installation Instructions, chapter 6, section Assigning the standard IP address using the DIP switch. Spectrometer is in stand-by mode. In this case, the status light on the spectrometer top side flashes green.
Deactivate the stand-by mode by pressing the SBY/ RES button at the spectrometer rear side shortly (about 1 sec.). See chapter 2, section 2.8.
Spectrometer IP address
Figure 69: Entering the Spectrometer IP Address in OPUS
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Troubleshooting
between ALPHA and PC To check the communication connection you can use either the Internet Explorer provided as part of Windows or any other internet browser program installed on your PC. Proceed as follows: 1 2
3
4
5
6
Open the internet browser. Make sure that the internet browser is not in the offline mode. In case of the Microsoft Internet Explorer, the offline mode is indicated by a tick in front of the Offline Mode command in the File menu of the browser. Make sure that the internet browser does not use a proxy server, at least, for addresses of direct access in the 10.10.x.x-range. In case of the Microsoft Internet Explorer, you can check this by selecting the Internet Options command in the Extra browser menu. Click on the Connections tab. Then, click on the Settings button in the LAN-Settings group field. Enter the standard spectrometer IP address in the corresponding browser entry field as follows: http://10.10.0.1/diag.htm. Then, press the Enter button. Now, the Internet Explorer should display the diagnostics page of your ALPHA spectrometer (see figure 70). If, however, the Internet Explorer displays a blank page and is not able to access the ALPHA diagnostics page a wrong spectrometer IP address is the cause of the problem Close the internet browser.
Figure 70: Diagnostics page of the ALPHA spectrometer
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Problem - Possible Causes - Solutions
8.3.3
Chapt. 8
P e r f o r m a n c e t e s t d o e s n o t s ta r t a u t omatically
Normally, the performance test starts automatically after OPUS has been opened again, after ALPHA has been accessed again or after the measurement module or the ATR crystal plate has been exchanged. If the performance test does not start automatically, the following problems may exist: Possible Cause
Solution
No measurement module is placed Snap the measurement module correctly into place in the basic module, or the measure- (see also chapter 2, section 2.6). ment module is not snapped properly in place. No ATR-crystal plate is installed or not installed properly.
8.3.4
Install the ATR-crystal plate properly (see chapter 6, section 6.2.3).
P e r f o r m a n c e Te s t f a i l e d
The performance test procedure comprises the following tests: • Signal-to-noise test • 100% line test If the performance test failed, an OVP - PQ Test Protocol (as pdf file) appears automatically. The pdf files with the PQ test protocol are saved automatically under OPUS path\Validation\Reports.
Figure 71: Test protocol of a failed performance test
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Troubleshooting
Possible Cause
Solution
As the performance test performs only one measurement, this test may fail under certain circumstances without a spectrometer problem or malfunction.
In this case we recommend to perform an instrument test which will normally be passed. To do this, click on the Instrument Test button in the OPUS wizard and wait until the test is completed (duration: about 5 minutes). If this measure does not solve the problem and the instrument test fails as well, see the following section 8.3.5.
Ensure that the spectrometer is not exposed to strong During the performance test, the spectrometer was exposed to strong vibrations and perform an instrument test. To do this, vibrations. click on the Instrument Test button in the OPUS wizard and wait until the test is completed (duration: about 5 minutes). The ambient temperature is too low so that the warm-up of 7 minutes was not sufficient.
Wait until the source has reached its operating temperature. Then, perform an instrument test by clicking on the Instrument Test button in the OPUS wizard. Wait until the test is completed (duration: about 5 minutes).
Transmission module: There is a Remove the sample or object. Then, perform an instrusample or another object in the sam- ment test by clicking on the Instrument Test button in the OPUS wizard. Wait until the test is completed ple compartment. (duration: about 5 minutes). ATR module: ATR crystal is dirty or there is a sample on the ATR crystal.
8.3.5
Remove the sample or clean the ATR crystal (see chapter 6, section 6.6). Then, perform an instrument test by clicking on the Instrument Test button in the OPUS wizard. Wait until the test is completed (duration: about 5 minutes).
I n s t r u m e n t Te s t f a i l e d
The instrument test procedure comprises the following tests: • Signal-to-noise test • 100% line test • Wavenumber accuracy test In case the instrument test failed an OVP - PQ Test Protocol (as pdf file) appears automatically. The pdf files with the PQ test protocol are saved automatically under OPUS path\Validation\Reports.
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Problem - Possible Causes - Solutions
Chapt. 8
Figure 72: Test Protocol of a failed Instrument Test
A l l t h r e e t e s ts f a i l e d Possible Cause
Solution
Defective spectrometer component
To find out which component is defective, click on the OPUS status light (figure 62). The Instrument Status dialog opens (figure 63). If the laser or the interferometer or the electronics or the automation or the detector is defective, contact Bruker service. In case of a defective source, replace the source as described in chapter 7 Maintenance and Repair, section 7.1.
A l l t h r e e t e s ts o r o n l y t h e s i g n a l - t o - n o i s e - t e s t or only the 100%-line test failed Possible Cause
Solution
Transmission measurement module: The IR beam has been obstructed by an object (e.g. sample) in the spectrometer sample compartment.
Remove the object and repeat the instrument test by clicking on the button Instrument Test in the OPUS wizard.
In case of an ATR module: No ATRcrystal plate is installed or is not installed properly.
Install the ATR-crystal plate properly (see chapter 6, section 6.2.3).
ATR crystal is dirty.
Clean the crystal (see chapter 6, section 6.6).
ATR crystal is damaged.
Order a new crystal plate with the corresponding ATRcrystal material. After receipt, replace the crystal plate (see chapter 6, section 6.2.3).
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Chapt. 8
Troubleshooting
Possible Cause
Solution
In the course of time, the hygroscopic KBr windows have become opaque to such a degree that the infrared transparency is seriously reduced.
Order new KBr windows (part no.: 1005847). After the receipt of the spare windows replace the existing windows. See chapter 7 Maintenance and Repair, section 7.3.
If the problem has a different cause...
...contact the Bruker service (see appendix E).
Only the wavenumber accuracy test failed Possible Cause
Solution
Laser wavenumber needs to be recali- Select the Setup Instrument Test command in the Valibrated. dation menu. Click on the Measure LWN button in the Setup OPV dialog. If the problem has a different cause...
8.3.6
...contact the Bruker service (see appendix E).
A Sp e c t r o m e t e r P r o b l e m i n d i c a t e d b y a n Error Message in OPUS
Error Message in OPUS
Possible Cause
Solution
Device not ready.
IR source has not yet Wait until the warm-up is completed. It reached its operating tem- takes about 7 minutes. perature.
End of average lifetime is The end of the specified nearly reached, spare lifetime of the source is part will be required. nearly reached.
Order a spare source (part no. 1005855). After the receipt, replace the old source (see chapter 7 Repair and Maintenance, section 7.1). Note: Despite this message measuring is still possible. To turn the OPUS status light green again click on the Ignore button in the Instrument Status Message dialog (figure 64). The message will be repeated in certain time intervals until you have replaced the source.
Source is broken.
IR source is defect.
Order a spare source (part no.: 1005855). After receipt, replace the old source as described in chapter 7 Maintenance and Repair, section 7.1.
Source is not connected
When you have replaced the IR source, the plug of the IR source is not connected at all or not connected properly.
Connect the source correctly (see chapter 7, Maintenance and Repair, section 7.1.
No accessory connected. There is no measurement Place the measurement module in the module connected to the basic module and lock it properly in posibasic spectrometer mod- tion (see chapter 2, section 2.6). ule.
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Error Message in OPUS
Possible Cause
Front sample not connected.
This message can appear Install the ATR-crystal plate properly only in case you work with (see chapter 6, section 6.2.3). an ATR module and no ATR crystal plate is installed or it is not installed properly.
Standby mode activated.
The spectrometer is in stand-by mode.
Deactivate the stand-by mode by pressing the SBY/RES button for about 1 second. This button is at the spectrometer rear side (see chapter 2, section 2.8).
Humidity out of range.
Air humidity inside the spectrometer is too high.
Replace the desiccant bags. See chapter 7 Repair and Maintenance, section 7.2.
Temperature out of range. Temperature inside the spectrometer is too high. Cause: Ambient temperature is too high.
Solution
Operate the spectrometer only in the ambient temperature range specified by the manufacturer. Specified temperature range: 18 - 35°C. (64 - 95°F)
An instrument calibration is required. ...
Note: This message Click on the Calibrate button (figure 68) appears every six and wait until the calibration is commonths. It is factory-set. pleted. The purpose of a regular recalibration is to ensure that the measurements are performed with a correctly set laser wavenumber.
Wrong accessory inserted, unable to run OVP tests. Can not run OVP tests, please check OVP Setup.
You use two different Make sure that the measurement module measurement modules. If defined in the planer and the actually you start the instrument connected module are the same. test automatically by the OPUS planer you have to define the module. If the defined module is not connected to the spectrometer these error messages appear.
Wrong accessory inserted, unable to run OVP tests. Can not run OVP tests, please check OVP Setup.
In case of a manual test start: the actually connected measurement module and the selected test channel in OPUS are different.
If an error message appears which is not listed above...
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Either connect the right measurement module or select the right test channel in OPUS. To do this, select the Setup Instrument Test command in the Validation menu. Select the correct test channel in the Setup OPV dialog. Note: The actually connected module and the selected test channel have to be the same. ...contact Bruker service (see appendix E).
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Troubleshooting
8.3.7
A problem indicated by the spectrometer diagnostic LEDs
The diagnostic LEDs are at the spectrometer rear side (see figure 67).
N o L E D l i g h ts Possible Cause
Solution
Spectrometer is not connected properly to the mains supply.
Check the power cord connection at both ports, the mains outlet and the POWER port at the spectrometer rear side. See ALPHA Installation Instructions.
No voltage is applied
Check whether the proper voltage is applied at the mains outlet to which the spectrometer is connected.
Short circuit in the mains adapter of power cable.
A short circuit is accompanied by a "ticking" sound in the mains adapter. Unplug the power cord immediately and contact Bruker service (see appendix E).
The yellow ACC LED does not light at all A permanent dark ACC LED indicates that there is no communication between the spectrometer and the computer. Possible Cause
Solution
Spectrometer is not connected to the computer.
Connect the spectrometer to the computer using the supplied data cable (crossover, Cat-5). See Installation Instructions, chapter 3.
The spectrometer is connected to the PC using the wrong cable type.
Connect the spectrometer to the PC using only the supplied cross-over, Cat5-cable. See Installation Instructions, chapter 3.
The RJ45-plug(s) of the data cable has Check the data cable cord connection at both RJ45(have) not been connected properly. ports, the ETH/LAN port at the spectrometer rear side and the Network/LAN port of the PC. See Installation Instructions, chapter 3 section 3.2. The IP address of the ALPHA spectrometer is not selected in OPUS or the wrong IP address has been selected.
Enter the correct spectrometer IP address in OPUS. To do this, select the Optic Setup and Service command in the OPUS Validation menu. The Optic Setup and Service dialog opens. Select the Alpha option in the Configuration drop-down list and enter the spectrometer IP address (by default 10.10.0.1) into the field below (Optical Bench URL). See figure 69.
The factory-set standard IP address of Reassign the standard IP address to the spectrometer the spectrometer (10.10.0.1) has been using the DIP-switch at the spectrometer rear side. See changed. Installation Instructions, chapter 6, section Assigning the standard IP address using the DIP switch.
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Chapt. 8
Possible Cause
Solution
Spectrometer is in stand-by mode. In this case, the status indicator on the spectrometer top side flashes green.
Deactivate the stand-by mode by pressing the SBY/ RES button at the spectrometer rear side shortly (about 1 sec.). See chapter 2, section 2.8.
T h e r e d E R R L E D l i g h ts p e r m a n e n t l y A permanent red ERR LED indicates an interferometer and/or laser problem. Note: During a trouble-free spectrometer operation, this red LED flashes in the rhythm of the scanner movement. Possible Cause
Solution
A spectrometer problem caused by the laser and/or interferometer.
Contact Bruker service (see appendix E).
Strong vibrations or other strong Put the spectrometer on a vibration-free surface. If this mechanical impacts on the spectrom- measure does not solve the problem, contact Bruker eter which impair the spectrometer service (see appendix E). operation
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A General
Sp e c i f i c a t i o n s Parameter
Specification
Dimension
22 x 30 x 25cm (w x d x h)
Weight
approx. 7kg
Power consumption
Maximal: 100 - 240VAC, 50 - 60Hz (max 1.3A)
Environmental conditions
• Operational temperature range: 18°C - 35°C (64 95°F) • Temperature variation: max. 1°C/h and max. 2°C/day • Humidity (non-condensing): less than 80 % (relative humidity) • Installation site: in a closed room, max. 2000m above sea level • Installation overvoltage category: II • Pollution degree: 2
Safety regulations met
Complies with EN/IEC 61010-1/08.2002 (Safety requirements for electrical equipment for measurement, control and laboratory use)
EMI regulations met
Complies with EN/IEC 61326/05.2004 (Electrical equipment for measurement, control and laboratory use - EMC requirements) 7500 - 360cm-1
Performance Spectral range
Optik
Electronics
Resolution
better than 2cm-1, optional better than 0.9cm-1
Wavenumber accuracy
Better than 0.01cm-1
Wavenumber reproducibility
Better than 0.04cm-1
Photometric accuracy
0.1 % T
Design
Sealed optics housing, convective desiccating
Source
Air-cooled (can be replaced)
Interferometer
RockSolid, gold mirrors, permanently aligned
Beamsplitter
Multi-layer coating on Quarz
Detector
DTGS
HeNe laser
ALPHA is a CLASS 1 LASER PRODUCT and contains a laser diode (850nm).
A/D converter
100kHz with 24bit
Connectors
Ethernet
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Appendix A
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Specifications
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B
Consumables Part Number
Description
1005855
IR source with housing, pre-adjusted
1000917
Desiccant bags
1005847
2x replacement window (KBr), frame-mounted
1006041
2x replacement window (ZnSe), frame-mounted
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Appendix B
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Consumables
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C
Dimensional Drawings A L P H A - T:
Figure 73: ALPHA-T - Isometric view
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Appendix C
Dimensional Drawings
Figure 74: ALPHA-T - Top view
Figure 75: ALPHA-T - Front view
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Appendix C
Figure 76: ALPHA-T - Front view, open module
Figure 77: ALPHA-T - Left side view, open module
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Appendix C
Dimensional Drawings
ALPHA-P
Figure 78: ALPHA-P - Isometric view
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Appendix C
Figure 79: ALPHA-P - Top view
Figure 80: ALPHA-P - Front view
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Appendix C
Dimensional Drawings
Figure 81: ALPHA-P - Right side view, module
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Appendix C
ALPHA-E
Figure 82: ALPHA-E - Isometric view
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Appendix C
Dimensional Drawings
Figure 83: ALPHA-E - Top view
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Appendix C
Figure 84: ALPHA-E - Front view
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D
Glossary
ATR
ATR is the abbreviation of Attenuated Total Reflection. and is also known as Internal Reflection Spectroscopy (IRS). Principle: • IR light is directed through an internal reflection element (ATR crystal) which requires a high refraction index. • Due to the internal reflection in the ATR crystal the IR light is repeatedly reflected on the crystal surface. The number of reflections depends on the refraction index as well as on the crystal length and thickness, as well as on the incidence angle of the IR light. • If a sample gets in contact with the crystal, it absorbs IR light at each reflection point of the crystal. Therefore, a good contact between sample and crystal has to be ensured. • The IR light absorbed by the sample is missing in the reflected beam. Thus, the reflected beam changes its intensity, which is recorded as absorption spectrum, depending on the wavenumber. Note: The sample needs to have a lower refraction index than the crystal to achieve total internal reflection.
Beamsplitter
A device used to produce two separate beams from one incident beam. Generally a coated substrate that reflects and transmits approximately equal portions of the incident radiation.
Calibration
The entirety of working steps to define the relation between analyte concentrations and the corresponding standard measurement values. Under specified conditions the analyte concentrations are indicated by an instrument, measuring system, or values which have been evaluated by material measuring or reference material.
Cross-over cable
Cable used for the direct connection of two workstations Network Interface Cards (NICs). NICs have been dedicated to send and receive lines. A crossover cable connects from the send line of one NIC to the receive line of the other NIC.
Detector
A device that converts incoming light into an electrical signal.
Ethernet
Ethernet is the most widely installed Local Area Network (LAN). A LAN is a network of interconnected workstations sharing the resources of a single processor or server within a relatively small geographic area (e.g. an office building). Ethernet is a set of hardware and signaling standards used for LANs. The most commonly installed systems are 10/100 BaseT.
Fourier Transform
The mathematical transformation used in FT spectroscopy to convert an interferogram into an infrared spectrum. Essentially, Fourier Transform decomposes or separates a waveform or function into sinusoids of different frequency which sum to the original waveform. It identifies or distinguishes the different frequency sinusoids and their respective amplitudes.
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Appendix D
Glossary
Frequency
The frequency is the number of periods per time unit. Since all electromagnetic waves travel at the speed of light, the frequency corresponding to a given wavelength can be calculated as: = c/
FT-IR
Fourier Transform InfraRed Spectroscopy A method to obtain infrared spectra of a sample using an interferometer and then performing a Fourier transform on the resulting interferogram to calculate the spectrum. In case of an FT-IR spectrometer infrared light emitted from a source is directed to an interferometer, which modulates the light. Leaving the interferometer the light passes through the sample compartment (and also the sample) and is focused onto the detector. The signal measured by the detector is called the interferogram.
Instrument test
The instrument test checks the spectrometer performance. It automatically runs when ALPHA communicates with the PC for the very first time. The test has to be repeated if the validity period (7 days) set by Bruker has been expired.
Interferogram
A plot of detector signal as a function of optical path length difference. Spectrometers are equipped with a broadband light source, which yields a continuous infinite number of wavelengths. The interferogram is the continuous sum, i.e. the integral of all the interference patterns produced by each wavelength. This results in the intensity curve as function of the optical retardation. At the zero path difference of the interferometer (x=0) all wavelengths undergo constructive interference and sum to a maximum signal. As the optical retardation increases different wavelengths undergo constructive and destructive interference at different points, and the intensity therefore changes with retardation. For a broadband source, however, all the interference patterns will never be simultaneously in phase except at the point of zero path difference, and the maximum signal occurs only at this point. This maximum in the signal is referred to as the centerburst. Any dispersive element in the beam path may lead to chirping of the centerburst.
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Interferometer
Inside the interferometer the light beam is splitted into two beams by the beam splitter. The most-commonly used Michelson interferometer consists of a beam splitter, stationary and movable mirror. Due to the continuous movement of one mirror the optical path lengths of the two separated beams changes in time. Interference is effected when the two light beams are recombined.
IP address
Network address of a workstation or network. IP addresses are always in the form of 4-number fields separated by dots. Each number field represents 1 byte. Values can be in the range of 0-255. The numbers on the left of the string define the network, the numbers on the right define the individual workstation or Network Interface Card (NIC).
Laser
The laser is a coherent source of monochromatic radiation. It is an essential part of the interferometer system. Due to laser light interferrence the position of the movable mirror (see Interferometer), and the data sampling positions are determined.
Micrometer (µm)
10-6 of a meter; a micron
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Appendix D
MIR
Mid InfraRed; covers the spectral range from 4,000 to 400cm-1 wave numbers. In this range fundamental vibrations are typically excited.
Performance test
The performance test checks the spectrometer performance. It automatically runs after starting OPUS, and exchanging a measurement module or ATR crystal plate.
Reflectance
Reflectance is the ratio of the radiation energy reflected from a surface to the radiation energy incident on the surface.
Reflection
The process by which incident illumination reacts with the sample and is converted to radiation energy that subsequently travels back from the sample surface at a defined wavelength.
Relative humidity
The amount of water vapor contained within an air sample, expressed on a scale of 0 - 100%.
Resolution
Resolution in FT-IR is determined by the maximum optical path difference reached in the measurement of an interferogram. The spectral resolution corresponds to the minimum possible spectral distance between 2 adjacent spectral lines which can be resolved by the spectrometer. It is produced by the instrumental spectral line shape and the line width of the sample’s absorption. The instrumental line shape is reciprocally related to the travel distance of the movable mirror in the interferometer, and also influenced by the apodization function and divergence in the interferometer. The higher the spectral resolution (smaller values), the higher the noise in the spectrum at a given measurement time.
Sample
Special kind of substance which is put into the sample position and measured.
Single-channel spectrum
The arithmetical transformation of the interferometer, the Fourier transformation, made by the spectroscopic software results in the so-called single-channel spectrum. This spectrum shows the intensity of each single wavenumber. The single-spectrum includes the entire spectral characteristics of the spectrometer, i.e. the signal detected by the detector as function of the wavenumber. This signal is influenced by the source type, beamsplitter transmittance, detector response etc.
Spectrometer
From the Latin word specere meaning image, and the Greek word metron meaning to measure. A spectrometer uses some sort of mechanical or electrical detection device to obtain the infrared spectrum of a sample. It contains a source of infrared radiation, a sample compartment to allow the radiation to interact with a sample, a detector for radiation and units to determine and display the intensity of radiation.
Spectrum
A spectrum is an image of radiation energy dispersed into its wavelength constituents or a two-dimensional plot of radiation energy or radiation energy ratio versus wavelength. It includes a set of absorption, reflection or transmission values which have been measured by an IR spectrometer based on defined wavelengths. The features in an infrared spectrum correlate with the presence of functional groups of molecules of a sample.
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Glossary
Transmission
A portion of the incident illumination energy passes directly through the sample without any interactions with electrons or molecules in the sample. Another portion of energy is absorbed and re-emitted over and over again in the same direction as the incident illumination. Transmission is the process of these events. In either case, the photons are transmitted through the sample.
Transmission measurement
In spectroscopy transmission is the classical method for the IR analysis of samples. Depending on the sample material, sample preparation can be very complex in case of transmission measurement. Principle: • IR light transmits a sample. • The sample absorbs specific wavelengths of the IR light. This kind of absorption of certain wavelengths enables to identify the sample. • If samples are evaluated for quantitative analysis, the intensity ratio of the IR light before and after passing the sample is measured within a specific wavelength.
Transmittance
Transmittance is the ratio of the beam energy transmitted through a sample to the beam energy incident on the surface of the sample.
Validation
During validation the x-axis (frequency) and y-axis (transmission, reflection) are verified by transmission or reflectance standards which may be included in the internal validation unit. The validation can be performed at individual time intervals by the application software.
Wave number
The term wave number is the commonly used dimension for the x-axis 1 in FT-IR spectroscopy. It is defined as ˜ = ----. The unit is cm-1. 0
Wavelength
110
The wavelength is the distance between two maxima on a sinusoidal wave, i.e. the distance traversed by one period of an electromagnetic wave. The wavelength depends on the refractive index of the medium which the electromagnetic wave travels through.
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E
Service Addresses Bruker Optik has an international network of branch offices and representations to ensure a competent customer service throughout the world. The following list includes the addresses of Bruker headquarters. For a complete list with the addresses and telephone numbers of the Bruker branch offices and representations worldwide, refer to the internet: http://www.brukeroptics.com/offices.htmll
North America Bruker Optics Inc 19 Fortune Drive, Manning Park Billerica, MA 01821 - 3991 USA Phone: +1 978 439 9899 (ext. 5227) Fax: +1 978 663 9177 www.brukeroptics.com [email protected]
Europe Bruker Optik GmbH Rudolf-Plank-Str. 27 76275 Ettlingen Germany Phone: +49 7243 504 619/600 Fax: +49 7243 504 698 www.brukeroptics.com [email protected]
Asia Bruker Hong Kong Ltd. Unit 509, 5/F, Tower II Enterprise Square No 9 Sheung Yuet Road Kowloon Bay Hong Kong www.brukeroptics.com Phone: +852 2796 6100 Fax: +852 2796 6109 [email protected]
No responsiblility can be taken for the correctness of this information. Subject to changes. Bruker Optik GmbH
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Index
In OPUS 88 Error Messages In OPUS 77 ETH/LAN Port 4 Ethernet 107
A ALPHA-E 8, 9, 54 ALPHA-P 7, 8, 55 ALPHA-T 5, 6, 46 Gas Cell 48 Liquid Cell 47 Sample Compartment 6, 47 Sample Holder 47 Atmospheric Compensation 17, 18 ATR Cleaning 59 Crystal Types 53 Height Adjustment 56 Measuring 51 Measuring Sample 58 Module 52 Placing Sample 57 Pressure Application Device 54 Sample Measurement 58 Spectra 60 B Baseline Correction 16 Basic Module 3
I Instrument Test 78, 86, 108 Interferometer 108 IR Source 62 Replacing 62, 64 K KBr Pellet 42 Kensington Lock 5 L Laser 108 LEDs 4 M Maintenance Instructions 61 Measurement 13, 14 Background 15 Procedure 14 Sample 15 Measurement Module Exchanging 9 O
C Calibration Line 37 Calibration Samples 36 CFG Switch 5 Communication Connection 83 Connecting Port 4 Consumables 95
OPUS Status Light 73, 81, 82 P Peak Pick 19, 21 Interactive 20 Performance Test 78, 85, 109
D
Q
Desiccant 65 Replacing 66 Detector 107 Diagnostic LEDs 78 Troubleshooting 90 Diagnostics LEDs Troubleshooting 90, 91
Quality Control 24 Procedure 24 Quantitative Analysis 35, 39 Method 36 Result 40 Quick Compare 24, 27 Method 25 Result 28 Quick User Guide 13
E Error Message Bruker Optik GmbH
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Index
R Reference Sample 24 Relative Humidity 109 S Sample Measurement 50 Sample Preparation 41 Methods 41 Service Addresses 111 Sigma 40 Specifications 93 Spectra Library 33, 34 Spectrometer Status Indicator 72, 79, 81 Spectrum Search 31 Result 32 Stand-by Mode 11 Substance Identification 31, 32 T TAP Port 5 Transmission Measurement 45 Troubleshooting 71, 74 V Validation 110 W Wave Number 110 Wavelength 110 Windows 67 Cleaning 70 Replacing 67, 68, 69
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