Rapid detection of neurotoxic insecticides in food using disposable acetylcholinesterase-biosensors and simple solvent extraction

The extensive use of pesticides to protect agricultural crops necessitates reliable tools for the detection of residues in food and water, thus ensuring environmental protection and consumer safety. Neuroinhibitors such as organophosphates and carbamates in particular, represent a potential hazard to human health. These compounds are frequently found in food but conventional methods of analysis are limited as they are either time consuming or not sufficiently sensitive. As a result, a rapid and sensitive biosensor test based on AChE-inhibition was developed. The disposable AChE-biosensor was directly applied in solvent extracts of food samples using isooctane as extraction solvent. A complete assay could be performed in less than 2 hours. Recovery rates of 84 % were obtained in tests with spiked orange juice samples. Tests in food samples with a lower water content resulted in reduced recovery rates (44 % for peach pap baby food). Phosphorothionate insecticides could be detected after direct oxidation in food with N-bromosuccinimide and solvent extraction. The assay displayed a detection limit of 2 μg/kg paraoxon which was sufficient for the monitoring of maximum residue limits in food according to EU regulations