Development of a new immunosensor for pesticide detection: a disposable system with liposome-enhancement and amperometric detection

The development of a disposable amperometric immunomigration sensor for the detection of triazine pesticides in real samples is presented. Thick film electrodes printed on PVC were used as strip-type transducers. Monoclonal antibodies against atrazine and terbutylazine served as biorecognition element. For the generation and amplification of the signal, hapten-tagged liposomes entrapping ascorbic acid as a marker molecule were chosen. A capillary gap and a wicking filter membrane strip served as migration zone. For signal detection on a graphite electrode, liposomes were lysed by Triton X-100 and the released ascorbic acid was quantified at a potential of + 300 mV vs printed Ag/AgCl. Signal response time was 1-3 min, acid sensitivity of measurements in tap water was below 1 mu g l(-1) of atrazine and terbutylazine. Atrazine determinations in soil extracts correlated well with standard procedures based on ELISA and HPLC. (C) 1998 Elsevier Science S.A. All rights reserved.