Synthesis and characterization of molecularly imprinted polymer embedded composite cryogel discs: application for the selective extraction of cypermethrins from aqueous samples prior to GC-MS analysis

Abstract

Molecularly imprinted particles embedded composite cryogel discs specific for α-cypermethrin and β-cypermethrin were prepared. Two different types of imprinted particles were embedded into cryogel to prepare composite cryogels specific for two isomers of cypermethrin simultaneously. Adsorption studies revealed that MIP is extremely selective for α-cypermethrin and β-cypermethrin with outstanding adsorption capacity. A sensitive analytical method comprising MISPE coupled with GC-MS has been developed to quantify trace levels of α-cypermethrin and β-cypermethrin in real water matrices. The polymer showed fast kinetics and follows a pseudo-second-order kinetic model very well (R² = 0.9999). It shows excellent capacity towards α-cypermethrin and β-cypermethrin with a higher total number of binding sites (N_t = 96 μmol g⁻¹ for α-cypermethrin and 95 μmol g⁻¹ for β-cypermethrin). The MIP showed selectivity over the homologues of α-cypermethrin and β-cypermethrin with imprinting factor (IF) 11.2, 10.0, 1.04 and 1.20 for α-cypermethrin, β-cypermethrin, deltamethrin and permethrin, respectively. The developed MISPE method followed by GC-MS enhanced the sensitivity and selectivity of the assay. This method was successfully applied to samples of lake water for the determination of α-cypermethrin and β-cypermethrin simultaneously. Moreover, the synthesized MIP can be easily regenerated and repeatedly used without loss of efficiency.