SIMULTANEOUS DETERMINATION OF POTASSIUM AND SODIUM BY OPTODE SPECTRA AND AN ARTIFICIAL NEURAL-NETWORK ALGORITHM

An optode device that contains two optical ion-selective membranes for potassium and sodium was used to obtain optode spectra of mixtures of these two ions, Such spectra are a non-linear function of the concent rations of the two ions, A back-propagation artificial neural network (BP-ANN) model was used to analyse these mixture optode spectra, The r esults showed that the BP-ANN technique is satisfactory for treating s uch non-linearity embedded in the data, In addition, an index for addr essing the quality of the model approximation was defined and shown to be highly effective in controlling over-fitting in BP-ANN training.