Least-squares support vector machines for simultaneous voltammetric determination of lead and tin: A comparison between LS-SVM and PLS in voltammetric data

Abstract

A differential pulse stripping method for the simultaneous determination of lead and tin is proposed. The procedure involves accumulation with dissolving of lead and tin on a hanging mercury drop electrode (HMDE), followed by oxidation of dissolve lead and tin by voltammetric scan using differential pulse modulation. The optimum experimental conditions are: 0.2 mol L −1 HNO 3, accumulation potential of −900 mV versus Ag/AgCl, accumulation time of 200 s, scan rate of 20 mV s −1 and pulse height of 80 mV. Lead and tin peak currents were observed in the same potential region at about −400 mV. The simultaneous determination of lead and tin by using voltammetry is a difficult problem in analytical chemistry, due to voltammogram interferences. The resolution of mixture of lead and tin by the application of least-squares support vector machines (LS-SVM) was performed. The linear dynamic ranges were 0.003–0.35 and 0.008–0.50 μg mL −1 and detection limits were 1 and 3 ng mL −1 for lead and tin, respectively. The capability of the method for the analysis of real samples was evaluated by the determination of lead and tin in real matrix samples with satisfactory results.