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

METALS
(d)
Aluminum metal
(e) Hydrogen peroxide (30%)
(f)
(g)
(h)
Potassium iodate solution:
(i) Stock solution:
Dissolve 0.3566 g of KIO 3 in water and dilute to 100 ml with water.
(ii) Working solution:
Dilute 5 ml of stock solution to 100 ml with water. Prepare fresh
daily.
Potassium iodide-sodium bicarbonate solution:
Dissolve 0.2 g of KI and 3 g NaHCO 3 in water and dilute to 100 ml
with water. Prepare fresh daily.
Starch indicator:
1 g of soluble starch and 20 g of NaCl dissolved in 100 ml water.
Note: Use boiled and cooled distilled water for preparation of reagents (f
and g).
Preparation of Sample:
Weigh accurately about 50 g of the homogenised sample into a clean silica
dish, add 2 g each of potassium dihydrogen phosphate and magnesium
nitrate and mix well. Add a few milliliters of water if necessary for mixing.
Evaporate the contents to dryness on a steam bath and char the dry product
on a burner by means of a soft flame. Transfer the dish to a muffle furnace
and ash the sample at about 500ºC for 6 to 8 hours and cool. If ash is not
carbon free moisten the sample with few milliliters of water, mix well, and
dry over a steam bath and ash at 500 º C for 1 hour.
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