Quality specification is the following: Appearance: white crystalline particles from mesh 5 to mesh 80 Assay: 99-101% Water content: 13-15% Melting point: 226-230 degree centigrade Free acid or Alkali: 4.5ML - 5.5ML Heavy metals: <10ppm O-toluene sulphonamide/P-toluene sulphonamide: complies with USP Arsenic: <2ppm Selenium: 30ppm max. Clarity of solution: lower than "1" clear Color of solution: lower than B9 Solubility: soluble in 1.5 parts of water 50 parts of ethanol 96% Benzoate & salicylate: no precipitate or violet color appearing Readily carbonizable substances: lower than standard The quality complies with USP24/BP98 standard.