Monohydroxycucurbit[7]uril-coated stir-bar sorptive extraction coupled with high-performance liquid chromatography for the determination of apolar and polar organic compounds.

A detailed study has been carried out on monohydroxycucurbit[7]uril-based stir-bar sorptive extraction (SBSE). A polydimethylsiloxane coating was produced by a sol-gel technique and doped with monohydroxycucurbit[7]uril ((HO)1Q [7]) as a selective sorbent phase. (HO)1Q [7] was chemically bound to the sol-gel silica substrate through hydrolysis and polycondensation. The coating possesses a porous surface, shows strong solvent resistance and good thermal stability, and has a long lifespan. Four groups of compounds, with polarities ranging from apolar polycyclic aromatic hydrocarbons to polar ketones, aromatic amines and phenols, were selected as test analytes. They were extracted with the coated stir bar, then desorbed with methanol and quantified by high-performance liquid chromatography with ultraviolet detection. The limits of detection range between 1.3 and 15 μg L-1, the linear ranges extend from 5 to 10,000 μg L-1, and the relative recoveries from spiked samples range between 76.4 and 97.9%. The intraday relative standard deviations range from 2.3 to 8.6% (for n = 3, at 500 μg L-1). Compared with a commercial PDMS-coated stir bar and a polyether sulfone-coated stir bar, the new stir bar shows wider applicability and better extraction efficiency for each group of compounds. In addition, the stir bar can simultaneously extract mixtures of chemicals of different polarities. This endows it with the potential for recovering a broad group of polar organic compounds. Graphical abstractA stir bar for sorptive extraction based on monohydroxycucurbit[7]uril has been prepared by a sol-gel technique. The stir bar coupled with HPLC with UV detection allows for the determination of a variety of polar compounds and multicomponent mixtures, respectively.