-ketoenamine covalent organic frameworks based magnetic solid-phase microextraction for rapid determination of 12 organophosphate esters in surface water

In this work, Fe3O4/Tp-BHBD beta-ketoenamine covalent organic framework (COF) was rapidly prepared. Then, it was used as magnetic solid phase microextraction (MSPE) adsorbents for the adsorption and determination of organophosphate ester (OPE) residues in surface water coupling with liquid chromatography-tandem mass spectrometry. The results of material characterization tests confirmed the generation of magnetized COF. The adsorption process was optimized by Box-Behnken Design and one-factor optimization experiments. After five use cycles, Fe3O4/Tp-DHBD still achieved good adsorption and high recovery. Under the optimal conditions, the developed Fe3O4/Tp-DHBD COF-MSPE-HPLC-MS/MS method obtained good linearity for 12 OPEs within 0.25-50.0 ng mL-1 and the limit of detection of 0.02-0.18 ng mL-1. The relative standard deviations were less than 8.6 %. Rapid detection and analysis of three samples from wastewater treatment plant showed that the recoveries of most of target OPEs at different spiked concentrations ranged from 62.0 % to 116.9 %, 60.9 %-115.1 %, and 60.4 %-112.9 %, respectively. In general, the established COF-MSPE method can provide convenient and satisfactory purification for OPEs compounds in surface water by adsorption and desorption, which is promising for specific applications.