standard testing procedure dibasic calcium phosphate

Storage Requirements:
Store protected from light and moisture.

Sampling:
Sample from each container / bag, if the consignment is of 03 or less than three containers / bags. If the number of containers / bags is more than 03and are up to 100, sample at randomly using the formula root (n) +1 where n is the number of containers/bags in the consignment. For the consignment of more than 100 containers/bags, sample additional containers/bags for every 100 containers/bags and thereafter. Collect a minimum of 5g from each of the randomly selected containers/bags in to individually no toxic, self sealing transparent polyethylene bearing ‘Sample For Analysis label kept in another transparent self sealing polythene bag. After completion of sampling return rest sample on the same container. Collect control sample in Pet bottle/Glass bottle.

Quantity of Composite Sample:

30 g

Quantity of Control Sample:

2 X 30 g

Description: A white, crystalline powder; odourless.

Solubility: Practically insoluble in water and in ethanol (95 per cent) it dissolves in dilute hydrochloric acid and in nitric acid.

Identification:

A. Gives reaction B of calcium salts (2.3.1)
B. The solution gives reaction C of phosphates (2.3.1).

Aci d-insoluble substances: Dry the residue at 105° for 1hour (0.1 per cent).

Arsenic: NMT 10ppm.

Heavy Metals: NMT 40ppm

Barium: The solution is not more opalescent than a mixture of 10ml of solution A and 0.5ml of distilled water treated in the same manner.

Iron: NMT 400ppm

Carbonate: No effervescence is produced.

Chloride: The solution complies with the limit test for chlorides (0.125 per cent)

Sulphates: NMT 0.5per cent

Nitrate: The blue colour does not appear.

Reducing Substances: The slight pink colour is not less intense than that produced by treating 1g of calcium carbonate in the same manner.

Proteinous impurities: No unpleasant odour is emitted.

Monocalcium and tricalcium phosphates: Disssolve 2.0gm 30.0 ml of 1M hydrochloric acid, add 20ml of water and 0.05ml

of methyl orange solution and titrate the excess of acid with 1M sodium hydroxide. Not less than 14.0 ml and not more

than 15.5ml of 1M hydrochloric acid (for anhydrous material )and not less than 110.0 ml and not more than 12.5ml of 1M hydrochloric acid (for the dehydrate) is required.

Loss on ignition: (2.4.20). : NMT 6.5 to8.5% w/w

Assay: 98.0% to 105.0%w/w on the anhydrous basis.

Description: A white, crystalline powder; odourless.

Solubility:
Practically insoluble in water and in ethanol (95 per cent) it dissolves in dilute hydrochloric acid and in nitric acid.

Identification:

A. Gives reaction B of calcium salts (2.3.1)
B. Dissolve 0.1g in a mixture of 5ml of 2M nitric acid and 5ml of water, The solution gives reaction C
of phosphates (2.3.1).

Acid-insoluble substances:
Heat 5.0g with a mixture of 40ml of water and 10.0ml of hydrochloric acid and dilute to 100ml with water. Filter, wash with hot water until the last washing is free from chloride and dry the residue at 105° for 1hour (0.1 per cent).

Arsenic:
Dissolve 1.0 g in 15ml of brominated hydrochloric acid, add 45ml of water and remove the excess of
Bromine with a few drops of stannous chloride solution AsT. The resulting solution complies with the
Limit test for arsenic (10ppm).

Heavy Metals:
Dissolve 2.5g in 20ml of 2M hydrochloric acid, filter if necessary and add 6M ammonia until a precipitate is formed. Add 2M hydrochloric acid just enough to dissolve the precipitate and dilute to 50ml with distilled water (solution A). 10ml of this solution complies with the limit test for heavy metals, Method A (40ppm)

Barium:
To 10ml of solution A add 0.5ml of 1m sulphuric acid, mix and set aside for 15 minutes. The solution
is not more opalescent than a mixture of 10ml of solution A and 0.5ml of distilled water treated in the
same manner.

Iron: 2.0 ml of solution A diluted to 10ml with water complies with the limit test for iron (400ppm)

Carbonate: Suspend 1 g in 5ml of water and add 2ml of hydrochloric acid; no effervescence is produced.

Chloride:
Dissolve 0.2g in water by the addition of 2ml of nitric acid. The solution complies with the limit test for chlorides (0.125 per cent)

Sulphates:
Dissolves 30.0 mg in 25ml of water by the addition of 2ml of hydrochloric acid . The solution complies with the limit test for sulphates (0.5per cent).

Nitrate:
To 0.1 g add 10ml of water, 10ml of nitrogen-free sulphuric acid and 1ml of indigo carmine solution and heat to boiling; the blue colour does not appear.

Reducing Substances:
Shake 1.0 g with 5ml of water and 5ml of 3 M sulphuric acid for 1minute. Add 0.1ml of 0.005M potassium permanganate and shake for 20 seconds. The slight pink colour is not less intense than that produced by treating 1g of calcium carbonate in the same manner.

Proteinous impurities: Heat 0.5g gently in a dry test tube; No unpleasant odour is emitted.

Monocalcium and tricalcium phosphates:
Dissolve 2.0gm 30.0 ml of 1M hydrochloric acid, add 20ml of water and 0.05ml of methyl orange solution and titrate the excess of acid with 1M sodium hydroxide. Not less than 14.0 ml and not more than 15.5ml of 1M hydrochloric acid (for anhydrous material) and not less than 110.0 ml and not more than 12.5ml of 1M hydrochloric acid (for the dehydrate) is required.

Loss on ignition :
6.5 to 8.5% (for anhydrous material) and 24.5 to 26.5 per cent (for the dehydrate),determined on 1.0g by igniting at 500°C.

Assay:
Weigh accurately about 0.3 g and dissolve in a mixture of 5ml of water and 1 ml of 7 M hydrochloric acid, add 25.0 ml of 0.1M disodium edetate and dilute to 200ml with water, Neutralise with strong ammonia solution, add 10ml of ammonia buffer pH 10.0 and 50mg of mordant black 11 mixture and titrate the excess of disodium edetate with 0.1 M zinc sulphate. Carry out the blank titration.