Selective and sensitive sensors based on molecularly imprinted poly(vinylidene fluoride) for determination of pesticides and chemical threat agent simulants

Abstract

Abstract Molecular recognition in molecularly imprinted polymers (MIPs) is attributed to complementary binding sites with same or similar size, shape, and functionality to imprint molecules. A new selective and sensitive sensor based on molecularly imprinted poly(vinylidene fluoride) (PVDF) polymer for the detection of methyl parathion (MP), a ubiquitous highly hydrophobic pesticide that is commonly used as a simulant of chemical threat agents. The PVDF-based sensor was prepared using the molecular imprinting method with a pre-polymerized PVDF instead of traditional in-situ or post- polymerized ones to avoid harsh and tedious polymerization conditions. In addition to size and shape of the imprinted cavities, the developed PVDF-based sensors could exhibit high selectivity and sensitivity mainly due to dipole-dipole interaction, hydrophobic interaction and van der Waals interactions with the template MP molecules. The results show that the prepared PVDF-based sensor indeed showed high selectivity towards MP against other pesticides such as diethyl phosphoramidate, dicrotophos, 2,4,5-trichlorophenoxyacetic acid, and terephthalic acid achieving a limit of detection (LOD) of 68.0 nM and a limit of quantitation (LOQ) of 226.8 nM using quartz crystal microbalance as sensor platform. The specificity and selectivity of the prepared MIP were further verified with detection of the analyte in spiked vegetable samples.