LAB MANUAL CHM580
EXPERIMENT 1
DETERMINATION OF Cr 2+ AND Cd 2+ IN PLANT TISSUE SAMPLES USING ATOMIC ABSORPTION SPECTROSCOPY (AAS)
OBJECTIVES:
1. To determine Cr 2+ and Cd2+ in plant tissue sample. 2. To familiarize with spiking technique in unknown sample
INSTRUMENT:
Atomic Absorption Spectroscop !AAS"# $icrowa%e &igestion
APPARATUS:
'eaker# (olumetric )lask# )ilter paper# filter funnel and pipette.
CHEMICALS:
Cr 2+ standard solutions of 1# 2# *# and , ppm Cd2+ standard solutions of 1# 2# *# and , ppm
SAMPLE
:
Spinach plant
Cut the sample into small pieces and put ,- g of the sample in o%en !11- oC" to dr for 2 hours. eigh *.- g of the sample and spike Cr 2+ and Cd2+ standard from each 1-- ppm standard solution into the sample. &i%ide the sample into * portions ranging from -., g to 1.- g accuratel and place in microwa%e digestion %essels separatel. Add / m0 of concentrated 3 * and 1 m0 of 232 into each %essel. Then digest the samples in the microwa%e for 2- minutes. 4emember to cool down the %essels to room temperature opening the lid. !5t takes 1 hour to cool down" PROCEDURE:
D!r"#$ !% Cr 2+ &$d Cd2+ '$'$!r&!#$ #$ !% &"* ,.#$/ A!"#' A,r*!#$ S*'!r'*- (AAS)
0UESTIONS :
1.
67plain a little bit about the digestion method used in this e7periment.
EXPERIMENT 2
DETERMINATION OF CAFFEINE IN TEA SAMPLES BY USING ULTRAVIOLET SPECTROSCOPY
OBJECTIVES:
1.
INSTRUMENT:
5nstrument $odel 8 9erkin 6lmer : 0ambda *,
APPARATUS:
'eaker# (olumetric flask# hot plate# pipette# filter paper and filter funnel
CHEMICALS:
1. 2. *.
SAMPLE:
&ried Tea 0ea%es
PROCEDURE:
&issol%e 2 g dried tea sample in 1-- m0 distilled water and boil for 1, min. After boiling and cool # filter the sample and mark up m0 %olumetric flask with distilled water !1--ppm". the diluted sample into ,- m0 %olumetric flask mark !1- ppm".
to 2,9ipette , m0 of and top up to the
shake at the obtain e7traction
To quantif caffeine concentration in tea sample.
Caffeine standard solution !2# # ;# < and 1- ppm" -.--, $ a3 CCl *
Take 1- m0 of the tea sample solution and pour into a separating funnel. Add 2- m0 of CCl * into the separating funnel and the mi7ture. The mi7ture will separate into 2# aqueous laer bottom and organic laer at the top. Centrifuge the mi7ture to laer separation. Collect the aqueous laer. 4epeat the procedure * times.
respecti%e
9ipette 1 m0 of the e7tract into , different of 1- m0 %olumetric flask. Add -.-# -.# -.;# -.< and 1.- m0 of a3 in flasks. Add distilled water to the mark. 4un the =(>(is and determine the concentration of caffeine in the sample.
EXPERIMENT DETERMINATION OF CAFFEINE AND ACETYL SALICYCLIC ACID IN AN ANALGESIC TABLET BY ULTRAVIOLET SPECTROSCOPY
OBJECTIVES:
To quantif caffeine and acetl salicclic acid in analgesic tablet
INSTRUMENT:
5nstrument $odel 8 9erkin 6lmer : 0ambda *,
APPARATUS:
'eaker# (olumetric flask and pipette.
CHEMICALS:
1.
Caffeine standard solution !2##;#< and 1- ppm"
2.
Acetl salicclic acid standard solution !2##;#<# and 1- ppm"
SAMPLE:
PROCEDURE:
Analgesic tablet
1.
9repare all the standard solution using deionized water.
2.
eigh to the nearest 1 g the sample# analgesic tablet pro%ided. Transfer the weighed solid into 2,- m0 flask. Add about 2-- m0 of deionized water to sample and fill the flask to the mark with
*.
Transfer accuratel -., m0 of the sample solution into each of three ,- m0 %olumetric flasks. &ilute each flask to mark with water.
.
?et read to record =( spectra and determine the concentration of caffeine and acetl salicclic acid in sample.
%olumetric dissol%e the deionized water.
the
the
EXPERIMENT DETERMINATION OF RIBOFLAVIN IN ENERGY DRIN3S BY FLUORESCENCE SPECTROPHOTOMETRY
OBJECTIVES:
To determine the mass of 4ibofla%in in some energ drinks b )luorescence spectrophotometr
INSTRUMENT:
)luorescence Spectophotometer
APPARATUS:
'eaker# (olumetric flask and pipette.
CHEMICALS: SAMPLE:
1. 4ibofla%in standard solution !-.2#-.#-.;# -.< and 1 ppm" 2. ,@ Acetic acid 6nerg drink
PROCEDURE:
A4
C%"#'& Pr*&r&!#$ &) Pr*&r&!#$ 5 166 **" !'7 .!#$ 5 R#,5&8#$ !&$d&rd: 9repare a 1-- ppm ribofla%in stock solution b accuratel weighing about ,- mg ribofla%in# transferring to a ,-- m0 %olumetric flask# and diluting to %olume with ,@ !%%" acetic acid# This should be stored in a cool# dark place. ,). Pr*&r&!#$ 5 16 **" !'7 .!#$ 5 R#,5&8#$ !&$d&rd &$d !&$d&rd '&#,r&!#$ '.r8: &ilute an aliquot of the stock solution# 181- to obtain 1- ppm working standard solution. &ilute aliquots of this with ,@ acetic acid to prepare standards of - !blank"# -.2# -.# -.;# -.< and 1.- ppm ribofla%in.!All of the solution need to be prepared in dark bottle and the bottle must be closed with aluminium foil".
B)
S&"* *r*&r&!#$ 9our -.2 m0 of energ drink into ,- m0 of %olumetric flask. &ilute the sample with ,@ acetic acid. 9repare triplicate samples. These samples are read for analsis using fluorescence spectrophotometr.
C)
P! 5 C&#,r&!#$ C.r8 =sing the standard calibration concentrations !7 a7is" and their fluorescence %alues ! a7is"# plot a calibration cur%e and from this cur%e# determine the amount of ribofla%in in sample.
EXPERIMENT 9 ANALYSIS OF ASPIRIN AND CAFFEINE IN COMMERCIAL APC TABLET USING FTIR
OBJECTIVES:
To determine the aspirin !acetlsalicclic acid" and caffeine content in A9C tablet.
INSTRUMENT:
5nstrument $odel 8 9erkin 6lmer : Spectrum 3ne !)T54"
APPARATUS:
'eaker# (olumetric flask and pipette.
SAMPLE:
A9C tablet
PROCEDURE:
S#d S&"* ! *r*&r: 14 M#!.r 5 &"* &$d 3Br 4emo%e the agate mortar and pestle from the dessicator. ?rind -.--1 g sample in agate mortar into powder. Add -.-<- g B'r into the sample powder. $i7 them using the pestle. Scrap and heap the mi7turein the center of the mortar and grind again for 1 minute. Beep the B'r back into the dessicator after use.
24 3Br *! Take one fourth of the B'r mi7ture and transfer into the collar of the handpress.9lace the an%il along with the longer die pin so that it comes into contact with the samples. 0ift the die set carefull b holding the lower an%il. $ake sure the collar stas in places. 3pen the handle of the handpress slowl and insert the die set into the handpress.Close the handle. 4otate the dial pressure until the upper ram of the handpress slightl touches the upper an%il on the die assembl. Tilt back the unit in order to hold the die set from falling off. 3pen the handle. 4otate the pressure dial clockwise in one half turn.Compress the mi7ture slowl while closing the handle in 2 minutes. Tilt back the unit# open the handle and remo%e the die set from the unit carefull.eigh and inspect the pellet. These samples are read for analsis to obtain an 54 spectrum. G! !% '&#,r&!#$ '.r8 5r !&$d&rd ASA ; C&55#$
