Rapid Determination of Six Tetracycline Residues in Aquatic Products by Ultra-high Performance Liquid Chromatography-Tandem Mass Spectrometry after Cleanup with Carboxymethyl Filter Paper-based Metal-Organic Framework/Molecularly Imprinted Polymer Film

A novel metal-organic framework/molecularly imprinted polymer (MOF/MIP) membrane based on carboxymethylated filter paper (CMFP) for the high-throughput and specific detection of six tetracycline residues in aquatic products was prepared by an in-situ growth method. The material combined the high specific surface area of MOF and the specific recognition capacity of MOF. Compared with traditional solid-phase extraction (SPE) methods, the enrichment and elution time was shortened from 45 to 15 minutes, and the problem of SPE column blockage was avoided. In the optimized method, extraction was performed using 0.1 mol/L Mcllvaine-Na2EDTA buffer (pH 4.0), and after pH adjustment to 6.0, adsorption onto three pieces of the CMFP@UiO-66-NH2@MIP membrane was performed for 9 min, followed by ultrasonic-assisted elution with 5% (V/V) acetic acid in methanol for 6 min; detection was carried out using ultra-high liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). All analytes showed good linearity in the concentration range of 2–500 μg/L (R2 ≥ 0.999 8), and the detection limit was as low as 0.62–0.95 μg/kg. Spiked recovery rates were in the range of 82.5%–96.8% with relative standard deviation (RSD) ≤ 4.13%. These figures of merit were significantly better than those of the national standard method with SPE. This material could be reused for more than 5 times, effectively reducing costs. This study provides an efficient and low-cost pretreatment method for the multiresidue detection of tetracyclines in aquatic products, which has important application value in the field of food safety monitoring.