Selective determination of penicillin G from tap water and milk samples using surface molecularly imprinted polymers as solid-phase extraction sorbent

Abstract In this study, a selective sample preparation method coupling surface molecularly imprinting polymers (SMIPs) with solid-phase extraction (SPE) was developed for the determination of penicillin G from tap water and milk samples. SMIPs for penicillin G were synthesized by using silica gel as supporting matrix, methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EDMA) as the cross-linker, methanolacetonitrile (1:1,v/v) as the solvents and 2,2′-azo-bisisobutyronitrile (AIBN) as the initiator. Characterization and adsorption experiments revealed that SMIPs exhibited large adsorption capacity, high recognition ability and high rate of mass transfer. Application of SMIPs in SPE followed by HPLC was done to selectively determine penicillin G from tap water and milk samples. Under the optimal conditions, the proposed method demonstrated high linearity with the concentration of penicillin G ranging from 0.12 to 200 μg mL-1. The limits of detection (LOD) in tap water and milk were 0.05, 0.03μg mL-1, respectively. The limits of quantification (LOQ) in tap water and milk were 0.25, 0.12 μg mL-1, respectively. The recoveries of penicillin G at three spiked levels were ranged from 78.9 to 85.5 % with intra-day and inter-day relative standard deviation values below 4.8 %.