AMPEROMETRIC DETECTION OF NITROGEN-OXIDES BY MEANS OF INTERDIGITATED ARRAY ELECTRODES

The detection of nitrogen oxides contained in air was investigated usi ng their redox cycles. NO and NO2 gases can be detected by means of in terdigitated array (IDA) electrodes made of Au that are fabricated on a gas-permeable membrane. The IDA electrodes were applied to a gas det ection system for the first time. Although the membrane is soft and fl exible, and has pores, the electrodes can be formed successfully on it by photolithography devised in our laboratory. Between the electrodes , redox cycles are produced, and, hence, the gas sensitivities increas e. The reactions in this redox cycles are not simple, and it was confi rmed that nitrate produced on the generator electrode reacts with NO g as on the collector in the NO detection system. The increase in sensit ivity based on the generation of the redox cycle in amperometric detec tion appears to be improved by decreasing the distance between the ele ctrodes.