Kinetic-photometric determination of EDTA, zinc and bismuth by interchange reactions of CN— groups

Abstract

The in situ formation of the nickel(II)-6-methylpicolinaldehyde thiosemicarbazone complex by means of interchange reactions of CN— groups occurs when nickel(II), 6-methylpicolinaldehyde azine and thiosemicarbazide are mixed at pH 4.5. The reaction is monitored spectrophotometrically at 396 nm. Several species cause interferences, and these effects can be used for their indirect determination. The most important compound in this context is EDTA. This Ni(II)-EDTA-6-methylpicolinaldehyde azine-thiosemicarbazide system also permits the indirect kinetic-photometric determination of trace amounts of zinc(II) and bismuth(III).