Evaluation of various N-phenylthiosemicarbazones as chromogenic reagents in spectrophotometric analysis.

The synthesis, physicochemical properties and interactions with metal ions of three new reagents of the N-phenylthiosemicarbazone family, namely pyridoxal phenylthiosemicarbazone, 3-hydroxypyridine-2-aldehyde phenylthiosemicarbazone and 2,6-diacetylpyridine bis(phenylthiosemicarbazone), as well as their ionization constants and the spectral features of their complexes with transition-element cations are reported. A photometric determination of cobalt with pyridoxal phenylthiosemicarbazone in perchloric acid medium is proposed and has been used in analysis of steels.