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 />
Preparation <strong>of</strong> St<strong>and</strong>ard Curve:<br />
Prepare reagent blank <strong>and</strong> st<strong>and</strong>ard curve by adding 0, 0.2, 0.5, 1.0, 1.5 <strong>and</strong><br />
2.0 µg Hg to series <strong>of</strong> digestion flasks. To each flask add 100 ml diluting<br />
solution. Finally add reducing solution <strong>and</strong> aerate st<strong>and</strong>ards as for samples.<br />
Plot st<strong>and</strong>ard curve from least squares linear regression <strong>of</strong> absorbance<br />
against µg <strong>of</strong> Hg. Determine µg <strong>of</strong> Hg in aliquot from curve. If µg <strong>of</strong> Hg<br />
falls outside the range <strong>of</strong> calibration, repeat determination with smaller<br />
aliquot <strong>of</strong> sample solution to bring µg <strong>of</strong> Hg into region <strong>of</strong> st<strong>and</strong>ard curve.<br />
From size <strong>of</strong> aliquot used, determine total mercury content in original<br />
sample.<br />
Concentration Hg (µg / Kg) = µg Hg<br />
gm test portion<br />
(Ref:- A.O.A.C 17 th edn, 2000 Official Method 971.21 Mercury in Food<br />
Flameless Atomic Absorption Method) / Manual Methods <strong>of</strong> Analysis for<br />
Adulterants <strong>and</strong> Contaminants in Foods I.C.M.R 1990 Page 141)<br />
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