Simultaneous determination of ethanol, fructose, and glucose at an unmodified platinum electrode using artificial neural networks

Dual pulse staircase voltammetry (DPSV)-a combination of pulsed electrochem ical detection and staircase voltammetry-is investigated for the simultaneo us determination of glucose, fructose, and ethanol in mixtures. Each analyt e is found to elicit a distinctive response at a platinum electrode in an a lkaline solution. A method is devised for visualizing the electrochemical r esponses of numerous mixtures of the three compounds simultaneously, and ap plication of this method reveals that the mixed responses contain character istics of the individual analytes approximately in proportion to their conc entrations but that the combination of the individual responses is not a si mple summation. Extraction of individual analyte concentrations from combin ed DPSV responses is subsequently achieved using artificial neural networks (ANNs), The effects of the amount of training data, the number of hidden n eurons, the hidden neuron transfer function, and the network training time are investigated. Large amounts of training data and a hidden layer with lo g-sigmoidal transfer functions are found to give the best results. Networks with relatively small hidden layers and relatively little training are fou nd to produce the most generalized models, giving the most accurate concent ration predictions when tested on analyte concentrations not present in the training data, The lowest rms errors achieved were 40 mu M, 40 mu M, and 0 .5 mM for fructose, glucose, and ethanol, respectively, over a range of app roximately 0-700 mu M for the sugars and a range of 0-12 mM for ethanol, Th e success of this novel combination of DPSV and ANNs opens new possibilitie s for the simultaneous detection of mixtures of aliphatic compounds, which are traditionally considered difficult to detect.