AMS 1440-01 Espectro Infrarrojo

A N A L Y T I C A L M E T H O D - S P E C I F IC IC A T I O N PREPARED BY ANALYTICAL SCIENCES SCIENCES LABORATORY LABORATORY

AM-S 1440-01 July 2001

EXXONMOBIL RESEARCH AND ENGINEERING COMPANY 600 BILLINGSPORT ROAD, PAULSBORO, NEW JERSEY 08066

SCREENING OF NEW OIL BLENDS AND ADDITIVES (INFRARED METHOD) 1.

Introduction

1.1 This revision includes both dual and single beam instrument methods within one procedure, reflecting the predominant use of Fourier Transform Infrared technology.

standard does not purport to address all of the safety problems associated with its use. It is the responsibility of whoever uses this standard to consult and establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.

1.2 The "Calculation" and "Report" sections have been revised to include more clarity in the interpretation of infrared test results as they relate to complementary specification test results.

3.

1.3 The procedure for screening incoming additives and base stocks, and greases has been extracted from the comparative method for finished lubricants, and moved to Appendix A.

3.2 ASTM E1421, Practice for Describing and Measuring Performance of FT-IR Spectrometers.

Referenced Documents

3.1 MLP13, "Mobil Lab Practice 13, General Methods of Infrared Absorption Analysis."

4.

Summary of Method

1.5 A procedure has been added that allows visual comparison of the sample scan to reference handblend scans that bracket the allowable variation in additive content (Appendix B).

4.1 An infrared scan of the new oil and/or additive blend is generated. The infrared absorbance spectrum of the base oil, or primary base stock component of the blend, is subtracted from that of the sample scan. Comparison of key additive peaks in the sample is made to a reference handblend, which has been similarly analyzed.

2.

5.

1.4 The procedure for preparing solid samples for analysis has been included in Appendix A.

Scope

2.1 This method is used primarily to identify and comparatively quantify additives in new oil and additive blends that have significant and unique infrared (IR) absorbances. The method may be used to confirm that no other nonformulation IR-absorbing additives or contaminants are present at detectable levels. 2.2 The method also provides a screening procedure for neat additives (not blended or diluted by the plant) and base stocks to confirm similarity to reference materials, and check for IRabsorbing contaminants. Similarly, greases can be screened using this procedure. 2.3 The method is applicable to all petroleum products and additives manufactured and/or purchased by ExxonMobil that are liquid or solid and which are compatible with potassium bromide (KBr) or zinc selenide (ZnSe) cells. 2.4 This standard may involve hazardous materials, operations, and equipment. This

Definitions/Terminology

5.1 HATR Accessory. Horizontal Attenuated Total Reflectance accessory for use (in this method) with very viscous liquids. 5.2 Reference Handblend. This is a laboratory prepared sample containing all the additives of the finished product, per each formulation to be screened.

6.

Apparatus

6.1 Infrared Spectrophotometer, capable of scanning from 4000 to 400 cm-1 (2.5 to 25 um). Either single beam or dual beam instruments are acceptable for use, Fourier Transform or dispersive infrareds. Follow the manufacturer's instructions for instrument setup, including dry gas purge recommendations. 6.2 Potassium bromide (KBr) cells, assorted pathlengths. Two matched KBr cells are required if a dual beam instrument is in use. 0.2 mm (200 um) and 0.1mm (100 um) are most commonly

COPYRIGHT © 2001 EXXONMOBIL RESEARCH AND ENGINEERING COMPANY ALL RIGHTS RESERVED

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AM-S 1440-01 July 2001

used, but the cell pathlength should be appropriate for the intensity of the absorbance bands of interest in the sample.

8.2 Keep flammable solvents away from infrared sources (inside instrument). Fire and/or explosion may occur.

NOTE 1: If base oil and handblend reference spectra are to be stored for later use, as in automated calculation routines, cell pathlengths for each cell used must be stored with the associated spectra. For information on cell calibration, consult MLP13.

8.3 Helium-Neon lasers used in FTIR spectrometers can cause retinal damage if eyes are exposed to beam. Keep the sample compartment cover closed during operation to avoid exposure.

9. 6.3 Horizontal Attenuated Total Reflectance (HATR) accessory, for the analysis of viscous additives, strongly absorbing additive concentrates, and/or greases. A trough plate accessory with a ZnSe crystal is recommended. NOTE 2: HATR accessories are made by a variety of manufacturers, and must be purchased specifically for your instrument. Alternatively, two KBr plates, 4 mm x 25 mm round, with a 0.025 mm (25 um) Teflon spacer, can be substituted. If viscosity is not an issue, a 0.025 mm (25 um) KBr cell can be used as well.

7.

Reagents and Materials

7.1 Reference Handblend, standard laboratory blended sample containing all the additives per each formulation to be screened. It is important to make this sample as accurately as possible to the formulation of the product being tested. 7.2 Base stock(s) similar to that of the sample being tested. The same base stock blend is best if available. Synthetic PAO and ester stocks should be used when appropriate. 7.3 Solvent for cleaning KBr cells. The solvent must be capable of dissolving and washing away residual lubes and/or additives. A 50/50 mixture of heptane and toluene has been found suitable. See MLP13 for additional information.

8.

Safety

8.1 Consult Material Safety Data Sheets for information on the solvents used for cleaning cells, as well as additives and base stocks used for handblends. Establish and follow appropriate safety and health practices.

2

Procedure 9.1 Instrument Performance Verification

9.1.1 Follow the instrument manufacturer's recommendations for calibration and instrument performance verification. This usually includes, but is not limited to, running a polystyrene test film. If a procedure is not provided by the manufacturer, consult ASTM E1421 for guidance on FTIR instrumentation; MLP13 for dispersive instruments. 9.1.2 Many FTIR instruments will automatically perform validation checks as part of the instrument start-up routine. 9.2 Single Beam Spectrometer Method 9.2.1 Analysis of New Oil and FreeFlowing Additive Blends, Slurries, and Premixes 9.2.1.1 Make certain the sample is free of visible air bubbles. An ultrasonic bath can be used to remove entrained air if necessary. 9.2.1.2 Fill the sample cell with the base oil or base oil blend. Make sure the cell is filled completely, and that there are no air bubbles. Record a background spectrum, then record the infrared absorbance spectrum. See Figure 1. NOTE 3: A new background spectrum is typically run before each sample for single beam instruments. This may be unnecessary if instruments are not purged. Each laboratory should establish a frequency for running background scans, recognizing that the frequency can change in laboratories where climate control is poor. 9.2.1.3 Using the manufacturer's software, store this spectrum for later calculations (Srefb).


AM-S 1440-01 July 2001

9.2.1.4 Remove and clean the cell. 9.2.1.5 Fill the cell with the reference handblend, and record the infrared absorbance spectrum. See Figure 2. 9.2.1.6 Using the manufacturer's software, store this spectrum (Sref ). 9.2.1.7 Remove and clean the cell. Fill the cell with the sample, and record the infrared absorbance spectrum. Store this spectrum (Ssam). 9.2.2 Analysis of Strongly Absorbing Liquid Additive Blends, Slurries, and Premixes 9.2.2.1 Follow the manufacturer's instructions for use, care and cleaning of the HATR accessory. Smear or pour a base stock similar to that used in the additive blend, slurry, or premix on the HATR window, being sure that no bubbles are against the crystal face. Cover the crystal face entirely. 9.2.2.2 If KBr disks are substituted for the HATR accessory, place a drop of base stock on one KBr disk. Place a 0.025 mm (25 um) Teflon spacer on top of the disk. Carefully, to avoid bubble formation, place a second plate on top, and lightly press down to form a capillary film. 9.2.2.3 Record the infrared absorbance spectrum of the base stock (Srefb). 9.2.2.4 After cleaning the HATR or KBr disks, similarly prepare and record a spectrum of a reference handblend of the additive blend, slurry, or premix (Sref ). 9.2.2.5 Clean the HATR or KBr disks, then prepare and record an absorbance spectrum of the sample (Ssam). 9.3 Dual Beam Spectrometer Method 9.3.1 Analysis of New Oil Blends and Free-Flowing Additive Blends, Slurries, and Premixes 9.3.1.1 Make certain the sample is free of visible air bubbles. An ultrasonic bath can be used to remove entrained air if necessary. 9.3.1.2 Fill reference cell with a base oil blend similar to the formulated product or the neat additive and place in the instrument reference

beam. Make sure the cell is completely filled, and that there are no air bubbles. 9.3.1.3 Similarly, fill the sample cell with the reference handblend, making sure the cell is completely filled and free of air bubbles. 9.3.1.4 Record the differential IR scan of the reference in absorbance (DSref ). 9.3.1.5 Remove and clean the sample cell. Replace the IR pen with one containing a different color of ink. Return the IR chart paper to the beginning of the reference scan. NOTE 4: If software that allows storage of spectra is in use, the differential scan can be stored for further calculations. 9.3.1.6 Refill the sample cell with the sample to be screened and place in the sample beam. 9.3.1.7 With the different color pen, run an absorbance scan on the same chart paper (DSsam). NOTE 5: If software that allows storage of spectra is in use, the differential scan can be stored for further calculations. 9.3.2 Analysis of Strongly Absorbing Liquid Additive Blends, Slurries, and Premixes 9.3.2.1 Follow the procedure given in 9.2.2.1 and 9.2.2.2 for sample preparation. 9.3.2.2 Acquire spectra following 9.3.1.2 through 9.3.1.7.

10.

Calculations

10.1 If using a single beam instrument, perform a 1:1 subtraction of the base stock spectrum, Srefb, from the reference handblend spectrum (Sref ). For dual beam instruments, work directly with the differential spectrum (DSref ). All spectra should be in absorbance. See Figure 3. NOTE 6: A 1:1 subtraction can give negative bands due to base stock absorbances, since base stock is less concentrated in the sample than in pure base stock. However, this will not affect analysis of the additive components and should be ignored. See Figures 4 and 5 for illustrations.

COPYRIGHT ©2001 EXXONMOBIL RESEARCH AND ENGINEERING COMPANY ALL RIGHTS RESERVED

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AM-S 1440-01 July 2001

10.2 Using the Formulation & Technical Standard (F&TS), or similar product guidance, identify key additive peaks. Ideally, these peaks should be unique to a particular additive component, or additive package. Avoid peaks that have base stock interferences, such as carbon-hydrogen bonding regions.

11.

11.1 Report as "Match" if sample meets all of the following criteria: •

Key additive peaks are within +/- 10% of the reference additive peaks, or in the case of a bulk receipt (non-manufacturing) facility, the manufacturing plant has investigated any additive levels outside of these limits, and found them to be acceptable.

•

Sample shows no evidence of contamination (peaks which are not present in the reference, and are not associated with allowable base stock interchange).

NOTE 7: Not all additives will be detected as unique absorbances. Not all additives will have detectable infrared absorbances in product matrices when dosage levels are relatively low. 10.3 Measure either the net absorbance or area of each of the key additive peaks. Record these values. This is illustrated in Figures 4 and 5. NOTE 8: Absorbances to be used in subsequent measurements should fall below approximately 1.5 AU. Above this, instrument response is not always linear. If the net absorbance value of the band of interest is greater than 1.5 AU, choose a cell with a smaller pathlength, or use HATR (See 6.2), and rerun the handblend, base stock, and the sample. 10.4 Calculate the absorbance or area per centimeter, by dividing by the cell pathlength in centimeters (Aref1, Aref2, etc.). NOTE 9: If software is available and used to automate calculations, make sure cell pathlength is accounted for in calculations. This may require that cell calibration values are stored and associated with specific reference scans. 10.5 Similarly, subtract the base stock spectrum, Srefb, from the sample spectrum Ssam, or use the differential scan for the sample (DSsam) if obtained with a dual beam instrument. Measure the net absorbance or area of each key additive peak identified in the reference product, and calculate the absorbance or area per centimeter (Asam1, Asam2, etc.). Compare the values obtained for the sample spectrum components to the reference subtracted spectrum. Determine the percentage of the reference handblend for each component: % Stock Component 1 = Asam1/Aref1 *100% % Stock Component 2 = Asam2/Aref2 *100%

4

Reporting

NOTE 10: It is suggested that the manufacturing plant provide a copy of their infrared spectra and results of key additive peaks to any internal bulk receipt facilities for comparison. 11.2 Investigate any sample where key additive peaks are outside of +/- 10% of the reference additive peaks. Report as "Match" if one or more of the following criteria are met: •

Measured variation is equal to or less than that specified in the product F&TS or similar product guidance (example: allowable variation of calcium level is 33% in some products, which may translate to a 33% allowable variation in measured sulfonate value).

•

Specific additives are within formulation tolerance as measured by a primary test procedure (examples: phosphorus by ICP vs. phosphate ester band by IR; phenolic inhibitor by MM872 quantitative method).

•

Additive level can be varied to meet product specifications per the product F&TS or similar product guidance (example: adjustment with additional pour point depressants). 11.3 Report as "No Match" if sample results

do not meet the above criteria. 12.

Quality Control

12.1 Quality control sample(s) can be chosen that are representative of the particular products manufactured or tested at a facility. Since the reported results are "Match" and "No Match", the


AM-S 1440-01 July 2001

stock component percentages calculated in 10.6 can be either charted or logged as precision monitors if desired.

13.

•

Appendix B, "Visual Comparison Method"

•

Figures 1-5, Spectra from Single Beam Spectrometer, Engine Oil and Hydraulic Oil

•

Figures 6-8, Visual Comparison Method

Precision and Bias

13.1 The standard estimates of repeatability and reproducibility are not applicable to this method.

15.

Document History

1986

14.

Additional Information 1991, 1995 July 2001

14.1 Attached are: •

Appendix A, "Screening Procedure for Incoming Additives, Base Stocks, and Greases"

Adopted Mobil Analytical Method Revised Revised, ExxonMobil L&PS, MTS Laboratory, Paulsboro, NJ

DISCLAIMER The method, and information upon which it is based, is believed by ExxonMobil to reflect sound scientific analytical techniques; however, ExxonMobil does not represent that the analytical method is error free. ExxonMobil makes no representations, warranties, or guarantees, with respect to its use. ExxonMobil shall have no responsibility hereunder to (the other party) or to (such party's) employees for any injury or harm, for loss of profits, consequential or indirect damages resulting from use of such information, or for liabilities relating to negligent acts or omissions by ExxonMobil's employees.


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AM-S 1440-01 July 2001

APPENDIX A SCREENING PROCEDURE FOR INFRARED ANALYSIS OF INCOMING ADDITIVES, BASE STOCKS, AND GREASES A.1

Introduction

A.6.2.2 KBr pellet press and die

A.1.1 This appendix describes a procedure for screening greases, incoming raw materials, additives, and base stocks for contaminants using infrared spectroscopy.

A.2

A.2.2 Additives can be free-f lowing or viscous liquids, or solids. A.2.3 Greases can also be screened using this procedure, compared to a laboratory or production "reference" sample.


A.3.1 MLP13, "General Methods of Infrared Absorption Analysis". A.3.2 ASTM E1421, Practice for Descri bing and Measuring Performance of FT-IR Spectrometers.

A.4

Summary of Method

A.4.1 An infrared scan of the sam ple is generated, and visually compared with that of a reference material obtained in a similar manner.

A.5


A.5.1

A.6

See Section 5.

Reagents and Materials See Section 7.

A.7.2 Reference additives and base stocks, representative of production as supplied by manufacturer. Grease handblend or representative production sample. NOTE A1: It may not be possible to obtain a true "reference" additive, but most suppliers will provide a typical sample that can be used for comparison with incoming shipments. A.7.3 Potassium bromide (KBr) powder, spectroscopic grade. Store in desiccator to avoid exposure to atmospheric moisture.

A.8

Safety

A.8.1

A.9

See Section 8.

Procedure

A.9.1 Follow Section 9.1 for instr ument performance verification. A.9.2

Sample Preparation

A.9.2.1 Free Flowing Additives and Base Stocks: Follow Sections 9.2.1.1-9.2.1.2. A.9.2.2 Viscous Liquid Additives, Strongl y Absorbing Additives, and Greases: F ollow 9.2.2.19.2.2.2. A.9.2.3 Solids

Apparatus

A.6.1

A.7

A.7.1

Scope

A.2.1 This appendix provides a screening procedure for neat additives (not blended or diluted by the plant) and base stocks to confirm similarity to reference materials, and check for IRabsorbing contaminants.

A.3

A.6.2.3 Pellet holder for instr ument sample compartment.

See Section 6.

A.6.2 The following are required t o prepare solid samples:

A.9.2.3.1 Weigh 1-3 mg of the solid reference sample into an agate mortar. A.9.2.3.2 Using the pestle, grind the sam ple until it is very finely divided.

A.6.2.1 Agate mortar and pestle 6


AM-S 1440-01 July 2001

A.9.2.3.3 Add 300 mg KBr powder in approximately three equal portions, using the pestle to mix, not grind, the sample and KBr powder uniformly together. A.9.2.3.4 Pour the mixture into t he die and place the die in the press. A.9.2.3.5 Follow the manufacturer's instructions to operate the press. Usually, 8-10 tons of pressure is required for 3-5 minutes, but some "micro" or hand presses have specific recommended conditions for preparation. A.9.2.3.6 Carefully remove the newly formed pellet from the die and place it in a pellet holder.

A.11

Report

A.11.1 Report as "Match" any sample scan that is similar to that of its reference, with no evidence of contamination. A.11.2 Report as "No Match" if dissimilar to reference, or any contaminants are detected.

A.12

Quality Control

A.12.1 Not applicable.

A.13

Precision and Bias

A.13.1 The standard estimates of repeatability and reproducibility are not applicable to this method.

A.9.3 Record the absorbance spectrum of the reference. If using software, store this spectrum (Sref ). A.9.4 Clean the cell, HATR, KBr disk, or mortar, pestle, and die. Similarly, prepare the sample in question. A.9.5 Record the sample spectrum in a similar manner, either storing the spectrum (Ssam), or using a different pen color on the same piece of chart paper.

A.10

Calculations

A.10.1 If the spectra have been stored electronically, recall the reference scan, and overlay the sample scan (Sref overlaid with Ssam). A.10.2 Examine the spectra carefull y for similarities and differences in peak location and relative intensity. Note the presence of any contaminants. NOTE A2: If examining spectra generated on solids prepared in KBr, bands in the OH regions can be due to water absorbed by the KBr. Follow the die and press manufacturer's instructions to minimize exposure to moisture during sample preparation. Suspected water contamination in solid additives may need to be confirmed by another technique.


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AM-S 1440-01 July 2001

APPENDIX B VISUAL COMPARISON METHOD

B.1

Introduction

B.1.1 This procedure allows an alternate means of determining whether a new oil or additive blend meets the criteria of AM-S 1440 using visual comparison.

B.2

Scope

B.2.1 This method is used to identify and comparatively quantify additives in new oil and additive blends that have significant and unique infrared (IR) absorbances. The method may be used to confirm that IR-absorbing additives and contaminants that should not be present are not detected in the sample. B.2.2 This procedure is useful for laboratories that do not have electronic data handling capabilities.

Based on this visual plot, a judgement is made as to whether the sample falls within the +/- 10% allowance for the method. B.4.4 This method cannot be used where additive solubility prevents proper preparation of a handblend at other than target dosages. Handblends made at other than the target additive dosages must be similar in appearance to the target blend. The blend should be clear and bright with no sediment. NOTE B1: Some finished products have an allowable slight hazy appearance. In this case, any handblends made at other than target dosages should be similar in appearance, with no significant increase in haze.

B.5


See Section 5.

B.3


B.3.1 MLP13, "General Methods of Infrared Absorption Analysis"

B.6

See Section 6.

B.3.2 ASTM E1421, Practice for Describing and Measuring Performance of FTIR Spectrometers.

B.7

B.4

B.8

Summary of Method

Apparatus

Reagents and Materials

See Section 7.

Safety

B.4.1 An infrared scan of the new oil and/or additive blend is generated. The infrared absorbance spectrum of the base oil, or primary base stock component of the blend, is subtracted from that of the sample scan.

See Section 8.

B.4.2 Comparison of this subtracted scan is made visually to three reference handblend scans. One is prepared to contain an additional 10% of all of the additives present; one is prepared with the targeted amounts; and the third is made with 10% less of all additives.

B.9.1.1 Using the formulation for the desired product, prepare:

B.4.3 Absorbance spectra are overlaid, after base stock absorbances are subtracted. 8

B.9

Procedure B.9.1

Handblend Preparation

•

A reference handblend at the targeted additive dosages,

•

A reference handblend containing all of the additives at a 10% greater dosage level, and


AM-S 1440-01 July 2001

•

A reference handblend containing all the additives at a10% lower dosage than targeted.

B.9.2 Instrument Performance Verification B.9.2.1 Follow Section 9.1.1. B.9.3

Single Beam Spectrometer Method

B.9.3.1 Follow Section 9.2. B.9.3.2 Collect spectra for all three reference handblends, the appropriate base stock or base stock blends, and the sample. B.9.3.3 Store all spectra using the manufacturer's software. B.9.4

Dual Beam Spectrometer Method

B.9.4.1 Follow Section 9.3 B.9.4.2 Collect spectra for all three reference handblends, and the sample, using the appropriate base stock or base stock blend in the reference beam. B.9.4.3 Either record all four spectra on the same chart paper, or store the spectra for later analysis using manufacturer's software.

B.10

Calculations

B.10.1 If using a single beam instrument, perform a 1:1 subtraction of the base stock spectrum, Srefb, from the each reference handblend (Sref1,2,3). Store each differential spectrum (DSref1,2,3). For dual beam instruments, work directly with the differential spectra that were recorded in B9.4.3. B.10.2 See Section 10.2, and Note 7.

sample, and base stock in a smaller cell or use HATR. B.10.4 Similarly, use a 1:1 subtraction to subtract the base stock spectrum, Srefb, from the sample spectrum, Ssam. Store this differential spectrum, DSsam. If working with a dual beam instrument, the differential scan has already been created for the sample in B9.4.2, and either charted, or stored electronically. B.10.5 If spectra are stored electronically, recall the differential scans of the "on target" handblend, and both the +/-10% blends. Recall the sample differential. Overlay these spectra on the same scale. Take care to ensure that the baselines are not offset. See Figures 6-7. B.10.6 Looking at the overlaid spectra, whether recalled electronically, or plotted on chart paper, ensure that the key additive peaks for the sample in question lie within the absorbance minimum and maximum limits created by the handblends. See Figure 8. B.10.7 Examine the differential spectra carefully for evidence of contamination (peaks which are not present in the handblend, and are not associated with allowable base stock interchange).

B.11

Report

B.11.1 See Section 11.

B.12

Quality Control

B.12.1 See Section 12.

B.13

Precision and Bias

B.13.1 The standard estimates of repeatability and reproducibility are not applicable to this method.

B.10.3 See Note 8. If absorbance values for key peaks exceed 1.5 AU, rerun the handblends,


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AM-S 1440-01 July 2001

FIGURES 1-5 SPECTRA FROM SINGLE BEAM SPECTROMETER, ENGINE OIL AND HYDRAULIC OIL 1. This is a typical absorbance spectrum of a base stock, 200 um cell. Paraffinic Neutral Base Stock, 200 um 3.0

2.5 A b s o r b a n c e

2.0

1.5

1.0

0.5

0.0 4000

3500

3000

2500

2000

1500

1000

500

1000

500

Wavenumbers 1: LPM3052: Paraffinic Neutral Base Stock, 200 um

2. This is a typical engine oil absorbance spectrum, 200 um. Typical Engine Oil, 200 um 3.0

2.5 A b s o r b a n c e

2.0

1.5

1.0

0.5

4000

3500

3000

2500

2000

1500 Wavenumbers

1: RN4598AA: Typical Engine Oil, 200 um

10


AM-S 1440-01 July 2001

3. When the base stock is subtracted from the reference handblend or sample spectrum, a differential spectrum like the one below results. Subtracted Spectrum, Engine Oil - Base Stock, 200 um

0.6

A b s o r b a n c e

0.4

0.2

0.0

-0.2

4000

3500

3000

2500

2000

1500

1000

500

Wavenumbers 1: RN4598AA: Subtracted Spectrum, Engine Oil - Base Stock, 200 um

4. Some of the key additive peaks are identified below, and their net absorbance values given. The hydrocarbon regions, which can give regions of negative absorbance after subtraction, are outlined in red, and should be ignored. The green box shows a negative absorbance due to carbon dioxide vapor differences, and should be ignored. Engine Oil Spectrum after Base Oil Subtraction, 200 um

0.5

A b s o r b a n c e

0.2649

0.4 0.1773

0.3

0.1234

0.1325 0.2

0.1

0.0

-0.1

4000

3500

3000

2500

2000

1500

1000

500

Wavenumbers 1: RN4598A: Engine Oil Spectrum after Base Oil Subtraction, 200 um


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AM-S 1440-01 July 2001

5. In this subtracted spectrum of a hydraulic oil, hydrocarbon regions are noted by red boxes, and should be ignored. Carbon dioxide vapor differences are outlined in green and should be ignored. In this product, key additive bands are noted with their net absorbance values. Hydraulic Oil after Base Stock Subtraction, 200 um

1.2

0.8947 1.0

A b s o r b a n c e

0.8

0.6

0.4

0.2

0.0343

-0.0

-0.2

4000

3500

3000

2500

2000

1500

1000

Wavenumbers 1: RL1546E-: Hydraulic Oil after Base Stock Subtraction, 200 um

12


500

AM-S 1440-01 July 2001

FIGURES 6-8 APPENDIX B: VISUAL COMPARISON METHOD 6. Below are three difference spectra of reference handblends prepared to contain 90 (green), 100 (blue), and 110% (red) of the targeted additive dosages. Reference Handblends, Difference Spectra, 90, 100, and 110% of Target Dosages

0.8

A b s o r b a n c e

0.6

0.4

0.2

0.0

-0.2

3500

3000

2500

2000

1500

1000

500

Wavenumbers

7. The difference scan for the sample is overlaid (in black). Reference Handblends, Difference Spectra, 90, 100, and 110% of Target Dosages

0.8

A b s o r b a n c e

0.6

0.4

0.2

0.0

-0.2

3500

3000

2500

2000

1500

1000

500

Wavenumbers


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AM-S 1440-01 July 2001

8. Key additive regions are expanded below to show that the production sample is between 90 and 100% of the target additive dosage. Production Sample vs. Reference Handblends

1706.51, 0.3655

0.40

A b s 0.30 o r b a n c 0.20 e

0.10

1780

1760

1740

1720

1700

1680

1660

Wavenumbers

Production Sample vs. Reference Handblends

974.84, 0.6446

0.70

1229.59, 0.5465

A 0.60 b s o 0.50 r b a n 0.40 c e 0.30

0.20

1300

1200

1100

1000

Wavenumbers

14


900

AMS 1440-01 Espectro Infrarrojo

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