Partial least squares calibration as a tool to overcome intermetallic interactions in the stripping analysis of metal ions: Application to the simultaneous determination of Pb(II), As(III), Cu(II), and Hg(II) using gold screen-printed electrodes

Abstract

This work explores the use of partial least squares (PLS) multivariate calibration to address the issues encountered in multianalyte differential pulse anodic stripping voltammetry (DPASV), particularly those arising from competition among metals for active sites on the working electrode and from the formation of intermetallic compounds. A simple and cost-effective method has been developed for the simultaneous determination of Pb(II), As(III), Cu(II), and Hg(II) ions in aqueous matrices by combining DPASV measurements using a commercial low-temperature gold screen-printed electrode (SPAuE) with a PLS-2 calibration model. The latter employs a central composite design (CCD) together with a new 4D-rotation strategy to ensure homogeneous distribution of concentrations for all four analytes. The methodology exhibits good analytical performance, with linear ranges up to 69 μg/L, R² values above 0.99, and repeatability and reproducibility below 8.9% and 11.9%, respectively. Additionally, it significantly improves accuracy compared to univariate calibration, achieving recoveries between 88.8% and 121.7%.