Surface Plasmon Resonance Nanosensor Development for Imidacloprid Detection Using Molecularly Imprinting Polymer

Imidacloprid (IMI) is an extensively used neonicotinoid insecticide, widely applied for effective pest control in various crops, as well as for the management of seed and soil pests. Monitoring IMI levels can provide important contamination risks, inform regulatory decisions regarding pesticide use, and guide strategies aimed at mitigating adverse environmental consequences. In this study, we focused on developing a surface plasmon resonance (SPR) nanosensor for IMI detection. Our initial step involved modifying the gold surface of the SPR chip. This was achieved through the self-assembly of allylmercaptane to form a monolayer, thus introducing polymerizable double bonds onto the chip's surface. After that, IMI imprinted poly(2-hydroxyethylmethacrylate–methacryloylamidoglutamicacid) [p(HEMA–MAGA)] film was designed on gold surface of SPR chip. The surfaces, both non-modified and IMI-imprinted p(HEMA–MAGA), were characterized using some analytical techniques, including atomic force microscopy (AFM), fourier transform infrared (FTIR) spectroscopy, and ellipsometry. The developed SPR nanosensor demonstrated a linear detection range between 1.0 ng L-1 and 10.0 ng L-1 and accomplished a limit of detection (LOD) as low as 0.33 ng L-1 and finally applied to the drinking water samples with high recovery.