Multidimensional voltammetry: Four-way multivariate calibration with third-order differential pulse voltammetric data for multi-analyte quantification in the presence of uncalibrated interferences

A four-way multivariate calibration approach based on the combination of differential pulse voltammetric (DPV) data and four-way algorithms is described for the first time. To achieve this goal, the DPV response of each sample was recorded thirty-six times. Six current-potential matrices were recorded at six different pulse durations. Each matrix consists of six vectors which have been recorded at six different pulse heights. The three-way data array obtained for the calibration set and for each of the test samples were joined into a single four-way data array. The recorded four-way data array was nonlinear, thus, the non-linearities were tackled by potential shift correction using correlation-optimized warping (COW) algorithm and subsequently was analyzed with unfolded-partial least squares/residual trilinearization (U-PLS/RTL) and multi-way-PLS/RTL (N-PLS/RTL) as third-order multivariate calibration algorithms. A comprehensive and systematic strategy for comparing the performance of the two algorithms was presented in this work, in particular with a view of practical applications. This comparison was developed to identify which algorithm offers the best predictions for the simultaneous determination of levodopa (ID), carbidopa (CD), methyldopa (MD), acetaminophen (AC), tramadol (TRA), lidocaine (LC), tolperisone (TOP), ofloxacin (OF), levofloxacin (LOF), and norfloxacin (NOF) in the presence of benserazide (BA), dopamine (DP), and ciprofloxacin (COF) as uncalibrated interferences using a multi-walled carbon nanotubes modified glassy carbon electrode (MWCNTs/GCE). This study demonstrated the more superiority of U-PLS/RTL to resolve the complex systems. The results of applying U-PLS/RTL for the simultaneous determination of the studied analytes in human serum samples as experimental cases were also encouraging. (C) 2015 Elsevier B.V. All rights reserved.