COF-COOH@MIP as solid-phase extraction adsorbent for selective and sensitive detection of metamitron in environmental water

Abstract

Metamitron (MET) is a selective herbicide widely used in agriculture but can persist in the environment and potentially contaminate water resources. This study reports the successful synthesis of a composite adsorbent, COF-COOH@MIP, specifically designed for MET preconcentration via solid-phase extraction (SPE) before high-performance liquid chromatography (HPLC) analysis. COF-COOH@MIP integrates the advantages of covalent organic frameworks (COFs) with their high surface area and stability and molecularly imprinted polymers (MIP) with their tailored recognition cavities. The adsorbent achieved a maximum adsorption capacity of 4.67μg mg−1. The SPE column packed with COF-COOH@MIP demonstrated excellent reusability, with recovery rates of MET around 100 % after six consecutive cycles. The limit of detection (LOD) and limit of quantification (LOQ) of the established method were remarkably low, at 2.94 ng mL−1 and 9.80 ng mL−1, respectively. The linearity was credible within 0.03-400μg mL−1 (R2 = 0.9999). The method’s applicability to real-world samples was validated by analyzing water from a farm, a ditch, and a river. This method offers a valuable tool for environmental monitoring programs to safeguard water quality from MET pollution.