Pesticide analysis with molecularly imprinted nanofilms using surface plasmon resonance sensor and LC-MS/MS: Comparative study for environmental water samples

Abstract

SPR sensor chip nanofilms were prepared using a molecular imprinting method. Characterization of nanofilms was achieved by fourier-transform infrared spectroscopy attenuated total reflectance (FTIR-ATR), contact angle, atomic force microscope, and ellipsometer. Kinetic and affinity binding of pesticides were investigated by binding pesticide imprinted and nonimprinted sensor chips to the SPR sensor. Comparative adsorption experiments for SPR sensors were performed to display the selectivity of pesticide imprinted nanofilms. Analysis of the SPR sensors revealed that imprinted nanofilms showed more sensitivity and selectivity than the nonimprinted ones for pesticide determination. Exact masses of molecular and fragmentation ions of pesticides were determined by liquid chromatography ion trap time-of-flight mass spectroscopy (LC/MS-IT-TOF). According to these exact masses and fragmentation ions, an LC–MS/MS method was prepared and validated for qualitative and quantitative analysis of the studied pesticides. The limit of detection values of dimethoate and carbofuran were found to be 16.92 ng L−1 and 20.47 ng L−1 in the LC–MS/MS method and 8.37 ng L−1 and 7.11 ng L−1 in the SPR sensor system, respectively. The accuracy and precision of both methods were determined by comparison of six replicates at three concentrations (50, 250, and 1000 ng L−1), using the same environmental water matrix for each pesticide. SPR sensors showed good accuracy, with recovery percentages between 90 and 95 for both pesticides. The results showed that SPR sensors have higher selectivity and sensitivity, and lower detection limits compared to LC–MS/MS.