Metal-organic framework-based molecularly imprinted polymers for dispersive solid-phase extraction of fluoroquinolones in coastal zone water and biological samples

Abstract

The coastal zone is a critical interface between terrestrial and marine systems, providing ecosystem services and economic value while serving as a major sink for land-derived contaminants. Identification and quantification of new pollutants (NPs) even at trace residues, particularly antibiotics in coastal environments, have attracted increasing concerns for their potential ecological and human-health risks. Given the complex, high-salinity matrices of coastal samples and low analyte concentrations, efficient sample pretreatment for cleanup and enrichment are required. Metal–organic framework-based molecularly imprinted polymers (MOF-MIPs), integrating the high porosity and surface area of MOFs with the molecular recognition ability of MIPs, have become promising sorbents for solid-phase extraction (SPE). Herein, a core–shell ZIF-8@MIPs composite was facilely synthesized via surface imprinting and one-pot precipitation polymerization using ciprofloxacin (CIP) as the template and the ZIF-8 MOF as the core. Morphology, structure and composition of the composite were well characterized, and the adsorption equilibrium could be reached within 30 min, with a high maximum adsorption capacity of 151.96 mg/g. Then the ZIF-8@MIPs-based dispersive SPE (DSPE) coupled with HPLC–UV was developed for the simultaneous enrichment and determination of six fluoroquinolones antibiotics (FQs) in coastal-zone water and biological samples. Under optimized conditions, low limits of detection of 0.060–1.440 μg/L and limits of quantification of 0.201–4.799 μg/L were achieved. Spiked recoveries in beach seawater, seaculture wastewater, river water, and biological samples (pomfret and prawn) ranged from 92.6% to 118.9%, with relative standard deviations (RSDs) from 0.2–6.1%. The present DSPE-HPLC study offered a simple and alternative way for NPs analysis in coastal samples, and could enrich the research connotations of MOF-MIPs-based sample pretreatment.