This applied project aims to develop a selective and sensitive analytical method useful for screening of neurotoxic insecticides in environmental samples based on combining the specific advantages of acetylcholinesterase biosensors and solid phase extraction (SPE). Biosensors offer low cost and ease of use, while pretreatment of samples with SPE ensures the necessary sensitivity and reliability of results by removing interferences from unknown samples. The successful combination of biosensors with SPE relies on the optimisation of enzyme inhibition in buffers containing optimised amounts of different water-miscible organic solvents and the appropriate choice of sorbent and eluent for analyte separation. A heterogeneous oxidation on the SPE column of organophosporothionate insecticides will be tested for improved sensitivity. The consortium combines the extensive experience of the National Research and Development Institute for Biological Sciences in the field of cholinesterase biosensors and enzymology with the know-how of S.C. CP MED Laboratory S.R.L. in solid-phase extraction, reliable analyses for environmental pollution monitoring and method validation.