Potassium Citrate (Tripotassium Citrate Monohydrate)

Potassium citrate is the tripotassium salt of citric acid, supplied as the monohydrate in the form of transparent crystals or a white to almost white granular powder. It is deliquescent on exposure to moist air, very soluble in water (one gram dissolving in about 0.5 mL) and practically insoluble in ethanol (96 per cent). On the monohydrate basis it delivers approximately 36.2 per cent elemental potassium, rising to 38.3 per cent on the anhydrous basis, which makes it one of the most potassium-dense food-approved salts that is neither chloride-based nor strongly alkaline in solution. Material is released against the USP monograph, which sets 99.0 to 100.5 per cent of C6H5K3O7 calculated on the dried basis, and against Ph. Eur. monograph 0400 and the corresponding BP text, which set 99.0 to 101.0 per cent on the anhydrous substance with water content controlled to 4.0 to 7.0 per cent by Karl Fischer. Pharmacopoeial grades also meet the Ph. Eur. limits for chlorides (not more than 50 ppm), sulphates (not more than 150 ppm), oxalates (not more than 300 ppm) and sodium (not more than 0.3 per cent). Potassium is the principal intracellular cation and an essential dietary electrolyte contributing to normal muscle function and normal functioning of the nervous system; potassium citrate is listed in Annex II of Directive 2002/46/EC as a permitted potassium source, and in food and beverage systems it is used as an acidity regulator, buffering agent and sequestrant under food additive number E 332(ii). Fine powder, granular and coarse crystalline grades are produced so that buyers can control dissolution rate and segregation in dry blends, and low-dust granular grades are usually preferred for effervescent and stick-pack lines. Because the salt is deliquescent, drums are heat-sealed with double liners and blending is best carried out below 45 per cent relative humidity. Each lot carries a certificate of analysis covering assay, water content, pH of solution, chlorides, sulphates, oxalates, sodium, heavy metals and microbiological limits, with kosher, halal, non-GMO and allergen-free declarations available. Shipments classify under HS 2918 15 10, India's specific tariff line for potassium citrate.