A flow injection voltammetric electronic tongue applied to paper mill industrial waters

A voltammetric electronic tongue with automated operation based on the flow injection (FIA) technique was applied to the characterization of wastewaters coming from the paper mill industry. A metallic multielectrode array – formed by platinum, gold and rhodium electrodes – was employed as the detection system, while the measurements were based on large amplitude pulse voltammetry (LAPV). LAPV consisted in scans of pulses from to 0 to 1.8 V at 0.2 V steps. Five current values were recorded for each pulse, so a set of 300 current values (three electrodes × 20 pulses × five values) was recorded for each sample. Samples were first discriminated using Principal Component Analysis (PCA), while Artificial Neural Networks were used for the characterization and prediction of chemical oxygen demand, conductivity and pH. The system may be used for the quick identification and monitoring of the quality of used waters in these industrial facilities.