Lab Manual Sept 2015

7/25/2019 Lab Manual Sept 2015

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LAB MANUAL

CHM580

EXPERIMENT 1


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DETERMINATION OF Cr2+AND Cd2+ IN PLANT TISSUE SAMPLES USING ATOMIC

ABSORPTION SPECTROSCOPY (AAS)

OBJECTIVES: 1. To determine Cr

2+

and Cd

2+

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: Cr2+standard solutions of 1# 2# *# and , ppm

Cd2+standard solutions of 1# 2# *# and , ppm

SAMPLE : Spinach plant

PROCEDURE: 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 Cr2+ 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"

D!r"#$ !% Cr2+&$d Cd2+ '$'$!r&!#$ #$ !% &"* ,-

.#$/ A!"#' A,r*!#$ S*'!r'*- (AAS)

0UESTIONS : 1. 67plain a little bit about the digestion method used in this

e7periment.

EXPERIMENT 2


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DETERMINATION OF CAFFEINE IN TEA SAMPLES BY USING ULTRAVIOLET

SPECTROSCOPY

OBJECTIVES: 1. To quantif caffeine concentration in tea sample.

INSTRUMENT: 5nstrument $odel 8 9erkin 6lmer : 0ambda *,

APPARATUS: 'eaker# (olumetric flask# hot plate# pipette# filter paper and filter

funnel

CHEMICALS: 1. Caffeine standard solution !2# # ;# < and 1- ppm"

2. -.--, $ a3*. CCl*

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

to 2,- m0 %olumetric flask with distilled water !1--ppm".

9ipette , m0 of the diluted sample into ,- m0 %olumetric flask

and top up to the mark !1- ppm".

Take 1- m0 of the tea sample solution and pour into a separating

funnel. Add 2- m0 of CCl*into the separating funnel and

shake the mi7ture. The mi7ture will separate into 2# aqueous laer

at the bottom and organic laer at the top. Centrifuge the mi7ture to

obtain laer separation. Collect the aqueous laer. 4epeat the

e7traction

procedure * times.

9ipette 1 m0 of the e7tract into , different of 1- m0 %olumetric

flask. Add -.-# -.# -.;# -.< and 1.- m0 of a3 in

respecti%e flasks. Add distilled water to the mark.

4un the =(>(is and determine the concentration of caffeine in the

sample.


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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##;#


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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


CHEMICALS: 1. 4ibofla%in standard solution !-.2#-.#-.;# -.< and 1 ppm"

2. ,@ Acetic acid

SAMPLE: 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.


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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.


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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"


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 -.-

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Lab Manual Sept 2015