Potassium Phosphate

Dipotassium Hydrogen Phosphate BP Ph Eur Grade Specifications
Dipotassium Phosphate BP

K2HPO4 -- 174.2 -- CAS 7758-11-4
Dibasic Potassium Phosphate BP
Potassium Phosphate Dibasic BP

DEFINITION
Dipotassium phosphate contains not less than 98.0 per cent and not more than the equivalent of 101.0 per cent of K2HPO4, calculated with reference to the dried substance.

CHARACTERS
A white powder or colourless crystals, very hygroscopic, very soluble in water, very slightly soluble in alcohol.

IDENTIFICATION
A. Solution S (see Tests) is slightly alkaline
B. Solution S gives reaction of phosphates.
C. Solution S gives reaction of potassium.

TESTS
Solution S
Dissolve 5.0 g in distilled water and dilute to 50 ml with the same solvent.
Appearance of solution
Solution S is clear and colourless.
Reducing substances
Heat on a water-bath for 5 min a mixture of 5 ml of solution S, 5 ml of dilute sulphuric acid and 0.25 ml of 0.02 M potassium permanganate. The solution remains faintly pink.
Chlorides
To 2.5 ml of solution S add 10 ml of dilute nitric acid and dilute to 15 ml with water. The solution complies with the limit test for chlorides (200 ppm).
Sulphates
To 1.5 ml of solution S add 2 ml of dilute hydrochloric acid and dilute to 15 ml with distilled water. The solution complies with the limit test for sulphates (0.1 per cent).
Arsenic
5 ml of solution S complies with limit test A for arsenic (2 ppm).
Iron
10 ml of solution S complies with the limit test for iron (10 ppm).
Heavy metals
Dissolve 2.0 g in 8 ml of water. Acidify with about 6 ml of dilute hydrochloric acid (pH 3 to 4) and dilute to 20 ml with water. 12 ml of the solution complies with limit test A for heavy metals (10 ppm).
Sodium
If intended for use in the manufacture of parenteral dosage forms, it contains not more than 0.1 per cent of Na, determined by atomic emission spectrometry.
Loss on drying
Not more than 2.0 per cent, determined on 1.000 g by drying in an oven at 125C to 130C.
Bacterial endotoxins
Less than 1.1 IU/mg, if intended for use in the manufacture of parenteral dosage forms without a further appropriate procedure for the removal of bacterial endotoxins.

Potassium Dihydrogen Phosphate BP BP Ph Eur Specifications
Monopotassium Phosphate BP BP Ph Eur Grade Specifications

KH2PO4 -- 136.1 -- CAS 7778-77-0
Monobasic Potassium Phosphate BP
Potassium Phosphate Monobasic BP

DEFINITION
Potassium dihydrogen phosphate contains not less than 98.0 per cent and not more than the equivalent of 100.5 per cent of KH2PO4, calculated with reference to the dried substance.

CHARACTERS
A white, crystalline powder or colourless crystals, freely soluble in water, practically insoluble in alcohol.

IDENTIFICATION
A. Solution S (see Tests) is faintly acid.
B. Solution S gives reaction (b) of phosphates.
C. 0.5 ml of solution S gives reaction of potassium.

TESTS
Solution S
Dissolve 10.0 g in carbon dioxide-free water prepared from distilled water and dilute to 100 ml with the same solvent.
Appearance of solution
Solution S is clear and colourless.
pH
To 5 ml of solution S add 5 ml of carbon dioxide-free water. The pH of the solution is 4.2 to 4.5.
Reducing substances
To 5 ml of solution S add 5 ml of dilute sulphuric acid and 0.25 ml of 0.02 M potassium permanganate. Heat on a water-bath for 5 min. The colour of the permanganate is not completely discharged.
Chlorides
Dilute 2.5 ml of solution S to 15 ml with water R. The solution complies with the limit  test for chlorides (200 ppm).
Sulphates
To 5 ml of solution S add 0.5 ml of hydrochloric acid and dilute to 15 ml with  distilled water. The solution complies with the limit test for sulphates (300 ppm).
Arsenic
0.5 g complies with limit test A for arsenic (2 ppm).
Iron
10 ml of solution S complies with the limit test for iron (10 ppm).
Sodium
If intended for use in the manufacture of parenteral dosage forms, it complies with the  test for sodium. Not more than 0.1 per cent of Na, determined by atomic emission spectrometry
Heavy metals
12 ml of solution S complies with limit test A for heavy metals (10 ppm).
Loss on drying
Not more than 2.0 per cent, determined on 1.000 g by drying in an oven at 125C to 130C.

Dibasic Potassium Phosphate USP Grade Specifications
Dipotassium Phosphate USP Grade Specifications

Dibasic Potassium Phosphate USP
Potassium Phosphate Dibasic USP
K2HPO4 174.18
Phosphoric acid, dipotassium salt.
Dipotassium hydrogen phosphate [CAS 7758-11-4].

Dibasic Potassium Phosphate contains not less than 98.0 percent and not more than 100.5 percent of K2HPO4, calculated on the dried basis.

Identification— A solution (1 in 20) responds to the tests for Potassium and for Phosphate.
pH: between 8.5 and 9.6, in a solution (1 in 20).
Loss on drying— Dry it at 105 to constant weight: it loses not more than 1.0% of its weight.
Insoluble substances— Dissolve 10 g in 100 mL of hot water, filter through a tarred filtering crucible, wash the insoluble residue with hot water, and dry at 105 for 2 hours: the weight of the residue so obtained does not exceed 20 mg (0.2%).
Carbonate— To 1 g add 3 mL of water and 2 mL of 3 N hydrochloric acid: not more than a few bubbles are evolved.
Chloride— A 1.0-g portion shows no more chloride than corresponds to 0.40 mL of 0.020 N hydrochloric acid (0.03%).
Sulfate— A 0.20-g portion shows no more sulfate than corresponds to 0.20 mL of 0.020 N sulfuric acid (0.1%).
Arsenic: 3 ppm.
Iron— the limit is 0.003%.
Sodium— A solution (1 in 10) tested on a platinum wire imparts no pronounced yellow color to a non-luminous flame.
Heavy metals: the limit is 0.001%.
Limit of fluoride— The limit is 0.001%.
Limit of monobasic or tribasic salt— Dissolve 3 g in 30 mL of water, cool to 20C, and add 3 drops of thymol blue TS: a blue color is produced, which is changed to yellow (with a greenish tinge) by the addition of not more than 0.4 mL of 1 N hydrochloric acid.

Monobasic Potassium Phosphate USP NF Grade Specifications
Monopotassium Phosphate USP NF Grade Specifications

Monobasic Potassium Phosphate USP NF
Mono Potassium Phosphate USP NF
Potassium Phosphate Monobasic USP NF
KH2PO4 136.09
Phosphoric acid, monopotassium salt.
Monopotassium phosphate [CAS 7778-77-0].

Monobasic Potassium Phosphate, dried at 105 for 4 hours, contains not less than 98.0 percent and not more than 100.5 percent of KH2PO4.

Identification— A solution (1 in 20) responds to the tests for Potassium 191 and for Phosphate.
Loss on drying— Dry it at 105 for 4 hours: it loses not more than 1.0% of its weight.
Insoluble substances— Dissolve 10 g in 100 mL of hot water, filter through a tarred filtering crucible, wash the insoluble residue with hot water, and dry at 105 for 2 hours: the residue does not exceed 20 mg (0.2%).
Arsenic: 3 ppm.
Lead— not more than 5 ppm of Pb).
Heavy metals— : the limit is 0.002%.
Limit of fluoride— The limit is 0.001%.

Potassium Metaphosphate USP NF Grade Specifications

Potassium Metaphosphate
KPO3 118.07
Metaphosphoric acid (HPO3), potassium salt.
Potassium metaphosphate [CAS 7790-53-6].

Potassium Metaphosphate is a straight-chain polyphosphate, having a high degree of polymerization. It contains the equivalent of not less than 59.0 percent and not more than 61.0 percent of P2O5.

Identification—
A: Add 1 g of finely powdered Potassium Metaphosphate, slowly and with vigorous stirring, to 100 mL of sodium chloride solution (1 in 50): a gelatinous mass is formed.
B: Boil a mixture of 0.5 g of Potassium Metaphosphate, 10 mL of nitric acid, and 50 mL of water for 30 minutes, and cool: the resulting solution responds to the tests for Potassium and for Phosphate.
Viscosity— Mix 300 mg with 200 mL of sodium pyrophosphate solution (3.5 in 1000), using a magnetic stirrer. Determine the viscosity of the clear solution obtained, or of the liquid phase of the mixture obtained after 30 minutes of continuous stirring: the viscosity is between 6.5 and 15 centipoises.
Lead— not more than 5 ppm of Pb.
Heavy metals—: the limit is 0.002%.
Limit of fluoride— To pass the test.

Potassium Phosphate Dibasic FCC
Dipotassium Monophosphate, Dipotassium Phosphate FCC Food Grade
Dibasic Potassium Phosphate FCC