A robust electrochemical sensing of molecularly imprinted polymer prepared by using bifunctional monomer and its application in detection of cypermethrin.

This work describes a hybrid electrochemical sensor for highly sensitive detection of pesticide cypermethrin (CYP). Firstly, Ag and N co-doped zinc oxide (Ag-N@ZnO) was produced by sol-gel method, and then Ag-N@ZnO was ultrasonically supported on activated carbon prepared from coconut husk (Ag-N@ZnO/CHAC). Finally, a layer of molecularly imprinted polymer (MIP) was in situ fabricated on glassy carbon electrode by electro-polymerization, with dopamine and resorcinol as dual functional monomers (DM), CYP acting as template (DM-MIP-Ag-N@ZnO/CHAC). Morphological features, composition information and electrochemical properties of DM-MIP-Ag-N@ZnO/CHAC were investigated in detail. It is worth to mention that for the first time response surface method was used to investigate the effect of double monomers and to optimize the ratio between template and monomers. Compared with typical one-monomer involving MIP, the MIP prepared with dual functional monomers (DMMIP) of monomers showed higher response and better selectivity. Under the optimal conditions, a calibration curve of current shift versus concentration of CYP was obtained in the range of 2 × 10-13~8 × 10-9 M, and the developed sensor gave a remarkably low detection limit (LOD) of 6.7 × 10-14 M (S/N = 3). Determination of CYP in real samples was conducted quickly and accurately with our sensor. The DMMIP-Ag-N@ZnO/CHAC electrochemical sensor proposed in this paper has great potential in food safety, drug residue determination and environmental monitoring.