Magnetic molecularly imprinted polymer based on dynamically established metal‐mediated binding sites for the determination of trace captopril in rat plasma

Abstract

Therapeutic drug monitoring of captopril, which is a commonly used antihypertensive agent in clinical practice, is necessary. However, matrix effect‐induced pretreatment is the bottleneck for determination. Metal‐mediated molecularly imprinted polymers, an essential branch of molecularly imprinted polymers with better specificity and selectivity, have been used to separate/enrich analytes from complex matrices. In this work, Cu2+ was introduced to dynamically establish the binding sites of metal‐mediated molecularly imprinted polymer towards captopril. All evidence demonstrated that the metal‐mediated molecularly imprinted polymer based on Cu2+ coordination obtained a higher adsorption capacity (81.23 mg/g), faster adsorption rate (adsorption equilibrium within 50 min), and better selectivity (with the unrecognized analog). Subsequently, the Cu2+‐mediated molecularly imprinted polymer was used as dispersive molecularly imprinted solid‐phase extraction to successfully establish an analytical platform for the determination of trace captopril in rat plasma. The enrichment factor was up to 20, the detection limit was as low as 0.16 μg/ml, and the average recovery was in the range of 87.51%–98.28% with a relative standard deviation of less than 3.29%. This study provides a promising reference for the preparation of selective adsorbents to improve pretreatment.