manual of methods of analysis of foods - Ministry of Health and ...

METALS
Preparation of Standard Solution:
Stock Solution: (1mg/ml)
Dissolve 0.19 g of AR grade SnCl 2 .2H 2 O in 5 ml of conc. HCl and make up
to 100 ml with distilled water.
Working Solution: (0.1 mg/ml)
Dilute 10 ml of stock solution to 100 ml with water.
Standard stock solution can also be prepared by dissolving a known weight
of pure Tin metal in conc. HCl and diluting to a known volume.
Pipette 20 ml of working solution to reduction flask and follow the method
as given for sample solution and find out the factor as follows:
µg of Tin in the aliquot of standard solution taken for reduction
Factor = ------------------------------------------------------------------------------
Titre volume (ml) of KIO 3 working solution (f – ii)
If this factor is differing from 297, then use that factor (instead of 297) for
calculating Tin content of sample.
(Ref:- Manual Methods of Analysis for Adulterants and Contaminants in
Foods, I.C.M.R 1990 Page 165)
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