Membrane protected multi-template molecularly imprinted polymer based micro-solid phase extraction coupled with high performance liquid chromatography for analysis of chlorophenols

Abstract

Multi-template molecularly imprinted materials (mt-MIPs) were prepared by surface imprinting and sealed into porous nylon membrane as micro-solid phase extraction (μ-SPE) device, coupled with high performance liquid chromatography (HPLC) to simultaneously extract and determine five typical chlorophenols (CPs) in leather matrices. By using well-prepared mesoporous silica modified multiwalled carbon nanotubes (MWCNTs@mSi) as supporting materials, and the mixture solution of five CPs as templates, the imprinted layer containing recognition sites of the CPs were formed via free radical polymerization. The as-prepared mt-MIPs were characterized by SEM, TEM, FT-IR and TGA, and the adsorption properties were investigated including static, dynamic and selective adsorption, showing high adsorption capacity of 39.15‒71.43 mg g⁻¹ and rapid mass transfer rate (within 30 min). Parameters affecting the extraction efficiency of membrane protected μ-SPE were optimized, including the type of membrane, amount of adsorbent, type and volume of desorption solvent, desorption time and salt effect. The established mt-MIPs-μ-SPE-HPLC method demonstrated satisfactory linearity of 2.0‒200 µg L⁻¹, high sensitivity with LODs of 0.17‒0.52 µg L⁻¹, and high enrichment factor (70.6‒144). Consequently, the method was successfully applied to the analysis of five CPs in tannery wastewater, finished leather and wet blue samples. Spike recoveries ranged from 73.00 %‒115.2 %, with RSDs of 0.28 %‒11.4 %, and matrix interference was examined to be negligible. The developed method proved viable for the simultaneous extraction and quantification of trace CPs in complex leather matrices.