Preparation of surface molecularly imprinted polymers as the solid-phase extraction sorbents for the specific recognition of penicilloic acid in penicillin

Abstract

A method coupling SMIP-SPE with high-performance liquid chromatography (HPLC) was established for the detection of trace amounts of PNLA in penicillin. Highly selective surface molecularly imprinted polymers (SMIPs) were prepared and used as solid-phase extraction sorbents for the specific recognition, enrichment, extraction and detection of penicilloic acid (PNLA) in penicillin. The polymers were characterised in terms of their physical and morphological properties by using SEM, FTIR, thermogravimetric analyses, nitrogen adsorption and desorption analyses and elemental analyses. The adsorption properties of the products obtained were studied, including the adsorption of isotherms, kinetics and selectivity. The results demonstrated that SMIPs possess a high adsorption capacity, rapid mass-transfer rate and high selectivity to PNLA when compared with non-imprinted polymers (SNIPs) and bulk molecularly imprinted polymers (MIPs). SMIPs adopted as the sorbents of solid-phase extraction (SMIP-SPE) were used to extract the penicilloic acid from the parent drug, the reusability and stability of which were investigated. The results of the method validation showed that the intra-day and inter-day accuracy were ≥93.2% and ≥90.9%, respectively. The RSD% of repeatability ranged from 0.7% to 6.8%, and that of the intermediate precision ranged from 4.9% to 7.4%. The limit of detection (LOD) and the limit of quantitation (LOQ) were 0.03 mg g⁻¹ and 0.1 mg g⁻¹, respectively. This work provides a promising method for monitoring the allergenic impurity in penicillin and improving the purity of penicillin.