Simultaneous determination of Cu, Pb, Cd, Ni, Co and Zn in bioethanol fuel by adsorptive stripping voltammetry and multivariate linear regression

• Simultaneous determination of six trace metals in bioethanol fuel samples.
• Multivariate determination of six analytes with a voltammetric method.
• MLR aided by variable selection provided excellent quantitative predictions.
• Peak alignment and baseline correction are crucial for DPAdSV signal processing.

In this work it is proposed the one-voltammogram simultaneous determination of Cu(II), Pb(II), Cd(II), Ni(II), Co(II), and Zn(II) at ppb and sub-ppb levels in bioethanol fuel samples by adsorptive stripping voltammetry. Mixed ligands were employed providing stripping peaks for all analytes at the same voltammetric scan under optimized conditions. To perform the determination, multivariate linear regression aided by successive projections algorithm (SPA–MLR) was evaluated. The voltammograms were preprocessed with the asymmetric least squares (AsLS) baseline correction algorithm and the icoshift peak alignment tool. An excellent analytical performance was obtained, despite the inherent complexity of the simultaneous determination, with average apparent recovery = 96% ± 16%, and better prediction results in comparison with the benchmark method of partial least squares (PLS).