Spectrophotometric determination of sulphonamides with metol and n-chlorosuccinimide [NCS], Dibromohydantoin [DBH] or N-Bromosuccinimide [NBS]

ABSTRACT

Ten sulfonamides are determined by interaction with NCS or DBH together with metol and measurement of the purplered color produced at 520 nm. These sulfonamides are sulfacetamide sodium, sulfamethoxazole, sulfaguanidine, sulfadimidine, sulfamethoxypyridazine, sulfamethoxydiazine, sulfaphenazole, sulfathiazole, phthalylsulfathiazole and succinylsulfathiazole. NBS is also used in conjuction with metol with the last five sulfonamides, not determined before by this procedure. The reaction is explained as involving oxidation of metol with NCS or DBH to p-N- methybenzoquinoneimine, followed by the formation of a purple red complex with the sulfonamide