Square-Wave Adsorptive Cathodic Stripping Voltammetric Determination of Trace Palladium Using 4-(2-Thiazolylazo)-Resorcinol

Abstract

A square-wave adsorptive cathodic striping voltammetry method has been established for trace determination of palladium. The method was based on the adsorptive enrichment of palladium(II)–4-(2-thiazolylazo)-resorcinol (TAR) complex at the hanging mercury drop electrode at pH 7–8 versus Ag/AgCl electrode. At the optimized stripping parameters of pH, scan rate, potential accumulation, deposition time, pulse amplitude, frequency, pulse width and TAR concentration, the established method exhibited good sensitivity and remarkable linear range of 0.5–53 µg/L for Pd. The limits of detection and quantification were 0.15 and 0.5 µg/L, respectively, with relative standard deviation of ±2.1% (n = 3) at 10 µg/L Pd. The developed method was judged by quantification of Pd in certified reference material (IAEA-Soil-7) and using inductively coupled plasma-mass spectrometry. The calculated Student t and F values did not exceed the tabulated t (2.18) and F (3.63) at P = 0.05, revealing no significant difference between the two methods. The method was free from the interference from most of the common anions, cations and surfactants present in water. The method was satisfactorily applied to the quantification of Pd in road dust and water samples.