Simultaneous determination of phenolic compounds by means of an automated voltammetric 'electronic tongue'

摘要

This contribution describes the simultaneous determination of three phenolic compounds, o-cresol, p-chlorophenol and 4- chloro- 3- methylphenol, using direct oxidation and amperometric detection coupled by signal deconvolution, accomplished via chemometric methods. Direct oxidation of phenolic compounds is performed at the surface of an epoxy-graphite transducer, by linear scan voltammetry. Due to strong signal overlapping, artificial neural networks (ANNs) were used during data treatment, in a combination of chemometrics and electrochemical sensors known as an ''electronic tongue''. To calibrate this system properly, a total of 80 mixed samples were prepared automatically by employing a sequential injection analysis (SIA) system designed to automatically generate the information needed to train the network. The phenolic compound concentration varied from 1 to 70 mu M for o-cresol, from 0.5 mu M to 140 mu M for p-chlorophenol and from 1 mu M to 100 mu M for 4- chloro- 3- methylphenol. A good prediction capability was obtained, with correlation coefficients > 0.964 when the obtained values were compared with those expected for a set of 24 external test samples not used for training. The results presented here indicate that this technique is a simple and robust analytical method of environmental interest.