Multienzyme electrochemical sensor array for determination of heavy metal ions

A multienzyme electrochemical sensor array is developed. It is based on capacitance pH-sensitive electrolyte-insulator-semiconductor (EIS) sensors with silicon nitride ion-sensitive layers and different forms of cholinesterase, urease and glucose oxidase as sensitive elements. With this sensor array, we used a multienzyme analysis to recognize the heavy metal ions in solutions containing a mixture of different metal ions, as well as for determination of their content in the analysed samples. The content of toxic elements was determined by estimation of the residual activity of enzymatic membranes after the injection of analysed samples. The conditions for enzyme sensors operation, such as buffer capacity, substrate concentration, time of incubation and time of response signal measurement, were optimised to reach the maximal sensitivity of multisensor for analysis of heavy metal ions in the investigated solutions. It was shown that multienzyme analysis followed by mathematical processing is an efficient approach to develop sensor arrays for toxic substrates detection. (C) 1999 Elsevier Science S.A. All rights reserved.