Screen-printed biosensors using different alcohol oxidases

Low-cost screen-printed sensors consisting of a platinum working electrode, a carbon counter electrode, and an Ag/AgCl pseudo-reference electrode were fabricated for the development of alcohol oxidase biosensors. The sensors were fabricated as amperometric transducers for the detection of alcohols in batch systems. A mixture of alcohol oxidase (AOD) with poly(carbamoyl)sulfonate (PCS) hydrogel was used for enzyme immobilization onto the platinum electrodes. Alcohol oxidases from different sources such as from Hansenula sp., from Candida boidinii and from Pichia pastoris were used for immobilization. The performances of the resulting different sensors has been compared and characterized with respect to enzyme load, pH and temperature dependence, response time, recovery time, linear range and sensitivity. The relative response of sensors for different alcohols was measured to evaluate the selectivity of the sensors. The effect of ascorbic acid and sodium sulfite as electrochemical interferents on the sensor's performance was investigated. The continuous operation and storage stability of the sensors were also evaluated. Most of the characterization parameters were found to be superior for sensors with immobilized AOD from Hansenula sp, The sensors were also tested with wine samples. The results obtained by the newly developed biosensors were compared to results obtained by pycnometry, the well-established reference method as well as gas chromatograpty method. (C) 2001 Elsevier Science B.V. All rights reserved.