磷酸单对硝基苯酚酯二钠盐中游离正磷酸的测定

Determination of Inorganic Phosphate Contained in p-Nitrophenyl Phosphate Disodium Salt

磷酸单对硝基苯酚酯二钠盐(O_2NC_6H_4OP(=O)(ONa)_2·6H_20,4-Nitrophenyl phosphate disodium salt hexahydrate,pNPP)

Inorganic phosphate contained in the unstable p-nitrophenyl phosphate (p-NPP) was converted to phosphomolybdic acid complex, and then separated from p-NPP by the extration of n-butyl acetate at 0℃. Finally, the content of inorganic phosphate was determined by photometric method at 720nm after the reduction of the phosphomolybdic acid complex by ascorbic acid in the presence of Sn^(2+) ion.