Discrimination and classification of wines based on polypyrrole modified screen-printed carbon electrodes coupled with multivariate data analysis

Abstract

This work demonstrates the application of voltammetric sensors based on screen-printed carbon electrodes (SPCEs) modified with polypyrrole doped with different doping agents for the rapid fingerprinting of different white and red wines followed by the discrimination and classification depending on grape variety and vintage year. Disposable SPCEs were used as working electrode for the electrochemical deposition of polypyrrole in the presence of different doping agents using chronoamperometry at a fixed potential of 0.8 V. Polypyrrole modified SPCE were used for direct analysis of wines, after appropriate dilution with 0.1 M KCl. Cyclic voltammograms illustrate waves corresponding to the electrochemical activity of the polypyrrole and doping agent, but also waves corresponding to the oxidation of different compounds, mostly phenolic compounds. Multivariate statistical analysis based on Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA) were used in order to evaluate the discrimination and classification capability of the proposed Ppy/DSA-SPCE for different white and red wines. LDA applied to the voltammetric data allowed to establish mathematical models able to classify some red and white wines by variety, with accuracy ranged from 50.00 % to 100.00 %. Also, the proposed electrochemical methodology was capable to discriminate young wines from old wines aged more than five years.