Assay (Acidimetric) 99.5 â101.0%Residue after ignition 0.02%Water 0.5%Insoluble matter 0.005% Chloride(Cl) 0.001%ste (PO4) 0.001%Sulte(SO4) 0.002%Arsenic(As) 0.0001%Heavy metals (as Pb) 0.001%Citric acid is a natural occurring fruit acid, produced commercially by microbial fermentation of a carbohydrate substrate. Citric acid is the most widely used organic acid and control agent in foods, beverages, rmaceuticals and technical applications.Citric acid occurs as colourless crystals or as white, crystaler with a strongly acidic taste. It is very soluble in water, freely soluble in ethanol (96 %) and sparingly soluble in ether.Citric acid is non- a low reactivity. It is chemically stable if stored at ambient temperatures. Citric acid is fully biodegradable and can be disposed of with regular waste or sewage.