Development of a hydrophilic molecularly imprinted polymer for the detection of hydrophilic targets using quartz crystal microbalance

In this study, we describe the development and applicability of a molecularly imprinted polymer (MIP) based on the facile modification of a hydrophobic polymer, poly(vinylidene difluoride) (PVDF), in a sensor for the detection of trichlorfon (TCF) as a representative hydrophilic organophosphate pesticide. This sensor was developed from its polymer as opposed to conventional in-situ polymerization methods. The performance of the TCF MIP sensor was evaluated using a quartz crystal microbalance (QCM) achieving a good linear response between 0-250 ppb and a limit of detection (LOD) of 4.63 ppb and a limit of quantitation (LOQ) of 15.77 ppb. The sensor demonstrated high selectivity in the presence of structural analogues including dimethoate, acephate, dichlorvos, malathion as well as carbaryl and carbosulfan. The sensor was also found to have satisfactory stability when monitored over a 20-day period. The developed method was successfully applied to detect TCF in spiked lettuce samples. The novelty of the proposed method lies in the assimilation of concepts from membrane modification into MIP sensor fabrication and demonstrates the possibility of utilizing polymers directly for a simple yet effective sensor development.