High-performance liquid chromatography of thiobenzamide derivatives with ultraviolet photometric and electrochemical detection

Abstract

Twenty-five thiobenzamide derivatives were separated on a reversed-phase system on various stationary phases, with UV photometric and voltammetric detection. The best results were obtained using a Partisil ODS column (10 μm, 250 mm × 4.6 mm I.D.) with a mobile phase consisting of 0.05 M sodium dihydrogen phosphate with 30% (v/v) methanol, containing 1.2 · 10 −4 M EDTA, at a flow-rate of 1.0 ml/min. Voltammetric detection on a carbon-fibre electrode at + 1.4 V (silver-silver chloride) is more sensitive than UV photometric detection at 254 nm, typical detection limits being ca. 0.1 and 1.0 ng. Voltammetric calibration curves exhibit good linearity and the measurements are reproducible (relative standard deviation of ca. 2%).