Thermo-magnetic dual-template molecularly imprinted polymers for simultaneous extraction and determination of multiple phenols by HPLC

High concentration of surfactant, lipid, metal salts, tanning agent, dye and other leather auxiliaries contain in wet-blue, crust leather and tannery wastewater. The existence of these complicated matrices seriously affects the performance of analytical instruments and the accuracy of conventional analytical methods. In this study, to effectively avoid matrix interference of leather and tannery wastewater by simple pretreatment process, thermo-magnetic dual-template molecularly imprinted polymers (TM-dt-MIPs) were prepared and used as magnetic solid-phase extraction (MSPE) adsorbent to simultaneously selective extract ten kinds of phenols (phenol, five chlorophenols (CPs), and four alkylphenols (APs)), coupled with HPLC analysis. The TM-dt-MIPs prepared by stimuli-responsive imprinting and multi-template imprinting techniques utilized magnetic graphene oxide-multiwalled carbon nanotubes as supporting material, N-isopropyl acrylamide and methacrylamide as functional monomers, 2,4-dichlorophenol and nonylphenol as dual template, showing uniform morphology, high magnetic property and thermal stability. Crucially, the thermo-sensitivity and adsorption ability for target phenols were assessed through thermo-regulated capture/release, static, dynamic and selective adsorption studies, confirmed that the adsorption and desorption of the target analytes could be effectively controlled by external temperature regulation and magnetic manipulation. The developed TM-dt-MIPs-MSPE-HPLC method exhibited excellent analytical performance, characterized by high enrichment factors (26.63–110.4), wide linear ranges (2–200 μg L −1 ), low limits of detection (0.10–0.36 μg L −1 ), limits of quantitation (0.34–1.21 μg L −1 ) and good precision (intra-day RSD: 1.61–6.84%; inter-day RSD: 2.15–8.51%). For the analysis of ten phenols in crust leather, wet blue, and tannery wastewater samples, satisfactory recoveries were achieved ranging from 72.27 to 119.6%, demonstrating the practical application prospects for trace phenol analysis in leather industrial matrices.