Spectrophotometric determination of zinc with biacetyl mono(2-pyridyl)hydrazone with application to its determination in tap waters and in alkali and alkaline earth metal chemicals

Abstract

A spectrophotometric method is proposed for the determination of zinc involving the measurement (at 440 nm in a pH 10 borate buffer containing 20% ethanol) of the yellow colour produced by zinc with biacetyl mono(2-pyridyl)hydrazone (BPH). The molar absorptivity is highly sensitive, about 52 000 l mol^–1 cm^–1. Conditions for optimum colour development and the nature of the reaction as well as interferences were studied. The method was applied to the determination of zinc in drinking waters and in pure alkali and alkaline earth metal chemicals. Good precision and accuracy were obtained.