Polarographic behavior of 2‐carboxybenzaldehyde thiosemicarbazone and the indirect trace determination of palladium(II) ions in catalysts

Abstract

AbstractThe electrochemical characteristics of 2‐carboxybenzaldehyde thiosemicarbazone (2CBTSC) have been studied by differential pulse polarography (DPP) and cyclic voltammetry (CV) at a mercury electrode. This new thiosemicarbazone is reduced in a two‐electron irreversible step at the nitrogen double bond of the side chain at pH 1.82. An anodic peak situated very close to the oxidation response of mercury has been observed by DPP in neutral and alkaline media. Determination of 2CBTSC based on the reduction peak is possible in the range of 5 × 10−8 M to 8 × 10−6 M, with a relative standard deviation of 2.3% in the middle of the range and a detection limit of 7.6 × 10−9 M (1.7 ng/mL). The decrease in the reduction peak of the thiosemicarbazone after the addition of Pd(II) has been used for the development of precise and sensitive amperometric determination of palladium in catalysts with an average relative error of 1.1% and a determination limit of 6ppb of Pd(II) (5.6 × 10−7 M).