manual of methods of analysis of foods - Ministry of Health and ...
manual of methods of analysis of foods - Ministry of Health and ...
manual of methods of analysis of foods - Ministry of Health and ...
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METALS<br />
Disconnect trap <strong>and</strong> mix solution in trap by gently drawing back <strong>and</strong> forth<br />
five times with aspirator assembly. Transfer this solution directly to<br />
spectrophotometer cell (glass stoppered preferred) <strong>and</strong> read absorbance at<br />
522 nm. Determine As 2 O 3 in aliquot from st<strong>and</strong>ard curve.<br />
Preparation <strong>of</strong> St<strong>and</strong>ard Curve:<br />
Place 0.1, 1.0, 2.0, 3.0, 5.0, 6.0 <strong>and</strong> 8.0 ml <strong>of</strong> st<strong>and</strong>ard solution containing 2<br />
µg As 2 O 3 /ml, in generator bottles. Add water to 35 ml <strong>and</strong> proceed as in<br />
‘Determination’. Plot absorbance against µg <strong>of</strong> As 2 O 3 .<br />
(Ref :- Manual Methods <strong>of</strong> Analysis for Adulterants <strong>and</strong> Contaminants in<br />
Foods I.C.M.R 1990 Page 147 / A.O.A.C 15 th edn Official Method 952.13<br />
Arsenic in Food , Silver diethyldithiocarbamate Method )<br />
3.3 DETERMINATION OF CADMIUM IN FOOD BY<br />
COLORIMETRIC DITHZONE METHOD<br />
Principle:<br />
The sample is digested with H 2 SO 4 <strong>and</strong> HNO 3 . The pH <strong>of</strong> the solution is<br />
adjusted to 9.0. The dithizone metals along with cadmium are extracted from<br />
aqueous solution with dithizone chlor<strong>of</strong>orm solution. Cadmium is separated<br />
from Cu, Hg <strong>and</strong> most <strong>of</strong> any Ni or Co present, by stripping CHCl 3 solution<br />
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