Voltammetric Determination of Pb, Cu and Hg in Biodiesel Using Gold Screen-printed Electrode: Comparison of Batch-injection Analysis with Conventional Electrochemical Systems

摘要

This article compares the use of batch-injection analysis (BIA) with a conventional batch system for the anodic stripping voltammetric (ASV) determination of Pb, Cu and Hg in biodiesel using screen-printed gold electrode (SPGE). The optimized BIA conditions were 200 mu L of injection volume of the digested samples at 5 mu Ls(-1) directly on the working electrode of the SPGE immersed in 0.1 mol L-1 HCl solution. Therefore, BIA-ASV presented the advantages of low sample consumption, which extended the SPGE lifetime to a whole working day of analyses, and potential for on-site analysis using battery-powered micropipettes and potentiostats. Although presenting lower sensitivity than conventional systems, the BIA-ASV presented detection limit values of 1.0, 0.5 and 0.7 mu gL(-1), respectively for Pb, Cu and Hg, a linear range between 20 and 280 mu gL(-1), and adequate recovery values (90-110%) for spiked biodiesel samples.