Spectrophotometric determination of zinc in potable waters and insulin with methylglyoxal bis(4-phenyl-3-thiosemicarbazone)

Abstract

This paper describes the interaction of methylglyoxal bis(4-phenyl-3-thiosemicarbazone)(MGBPT) with a range of cations in aqueous dimethylformamide. A spectrophotometric method is proposed for the determination of zinc in potable waters and insulin. The method is based on the reaction of MGBPT with zinc, which produces an intense yellow MGBPT-Zn (1 : 1) complex that has an absorption maximum at 455 nm at pH 6.4 and obeys Beer's law in the concentration range 0.2–4 p.p.m. The method is compared with the other proposed thiosemicarbazone procedures for the spectrophotometric determination of zinc.