4 Chloro 2 Amino Phenol 6 Sulphonic Acid ( 4 CAPSA) Empirical Formula: C6H6O4NSCl CAS no.: 88 - 23 - 3 Purity: 90 % Minimum. Molecular Weight : 223.5 gm/ mol. Appearance: Greyish Moist Powder Insolubles: 0.1 % Maximum Iron Content: 100 ppm Maximum Moisture Content: 4 % Maximum We can even offer a dry state of this product, with moisture content of 0.5% maximum.