Ultrasensitive Biosensors for the Detection of Insecticide Residues in Fruit Juices

Abstract

A highly sensitive and rapid fruit juice-screening test based on a disposable screen-printed TCNQ-modified biosensor was developed, which is suitable for monitoring anticholinesterase pesticides. The biosensor analysis was based on direct measurement of enzyme inhibition in pH-adjusted samples. It could detect levels of carbofuran, carbaryl, and chlorpyrifos oxon of 0.2, 0.9, and 1.1 μg.L-1, respectively, and thus clearly fulfills the demands of both Brazilian and EU regulations. To evaluate the biosensor efficiency, recovery rates were determined and were on average 93.9% (RSD from 5.9 to 18.5%) in untreated fruit juices. The proposed AChE biosensor has shown enough sensitivity and reproducibility to be used as a complementary technique to the chromatographic ones in food pesticide monitoring.