β-Cyclodextrin molecularly imprinted solid-phase microextraction coatings for selective recognition of polychlorophenols in water samples

A series of β-cyclodextrin derivatives were designed and synthesized. The derivatives were investigated as functional monomers in molecularly imprinted polymeric solid-phase microextraction (MIP-SPME) fiber coatings. The coatings, with a layer thickness of 250 μm, were immobilized onto stainless steel using a capillary tube as a mold. This study employed a simple, easy, and reproducible method to prepare uniform coatings for polychlorophenols extraction. The combination of molecular inclusion effects and the molecular imprinting sites was expected to enhance the molecular recognition ability for polychlorophenols. Compared with non-imprinted polymer coatings and MIP coatings with methacrylic acid as the functional monomer, the β-cyclodextrin MIP-SPME coatings exhibited significantly higher extraction amounts and excellent selectivity to the template of triclosan. The MIP-SPME coatings exhibited a favorable synergistic extraction capacity resulting from the β-cyclodextrin cavity and molecularly imprinted binding sites. The method of β-cyclodextrin MIP-SPME coupled with high performance liquid chromatography (HPLC) for triclosan and polychlorophenols analysis in real water samples was developed. The limit of quantification was 1 μg/L for the three polychlorophenols. The recovery for three analytes ranged from 83.71% to 109.98%, with the relative standard deviation (RSD) of 2.83% to 12.19%. The β-cyclodextrin MIP-SPME fiber coatings could be used for at least 100 cycles.