A chemometric-assisted voltammetric method for simultaneous determination of four antioxidants in biodiesel samples

A methodology for direct and simultaneous determination of four phenolics antioxidants – butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propyl gallate (PG), and tert-butylhydroquinone (TBHQ) – in biodiesel samples using differential pulse voltammetry (DPV) associated with partial least squares (PLS) regression is presented. Measurements were taken directly in biodiesel:ethanol 1:1 (v/v) medium using a platinum ultramicroelectrode (ume) as working electrode. The voltammetric signals of the compounds overlapped significantly, and to facilitate the simultaneous determination of the analytes, a PLS chemometric tool was applied and approaches fitting one compound at a time (PLS-1) and multiple compounds (PLS-2) both allowed the quantification of the individual concentrations, overcoming the strongly overlapped voltammograms. Results show that the PLS-2 model provides more accurate predictions than PLS-1. For the PLS-2 model, root mean square errors of prediction (RMSEP) of 3x101, 16, 24 and 3x...