Performance of a portable biosensor for the analysis of organophosphorus and carbamate insecticides in water and food

The performance of a portable biosensor prototype for the determination of neurotoxic pesticides in water and food samples has been assessed and validated for an in-field use. The biosensor is based on the inhibition of the acetylcholinesterase enzyme using screen-printed electrodes and an own designed potentiostat. Quality parameters have been tested using chlorpyrifos–oxon as reference compound. The lower concentration detected was of 2 μg/L for an enzymatic charge of 10 mU, the linearity was near to one order of magnitude and the repeatability was of 4.7% (n = 5) at 4 μg/L. Spiked and non-spiked water samples, beverages and vegetable extracts were used to validate the system and for pepper extracts, the response was compared to HPLC-MS. In these samples, the biosensor was able to detect pesticide concentrations in the order of the tenth of μg/L, although an important matrix effect was observed which was eliminated by calibrating the system with the same matrix as the sample to be tested. Measured concentrations were comparable to those obtained using commercial laboratory potentiostats and thus the suitability of the biosensor prototype for field application was proved.