Cotton thread modified with ionic liquid-copolymerized polymer for online in-tube solid-phase microextraction-HPLC analysis of non-steroidal anti-inflammatory drugs.

Cotton fiber is a kind of biodegradable material which possesses the properties such as high specific area, adjustable shape and hygroscopicity. In this work, organic polymer was directly in situ grown on the surface of cotton thread and packed into PEEK tube for online in-tube solid-phase microextraction. The novel strategy solves the problems like high backpressure and tedious optimization process of normal monolithic polymer based in-tube SPME capillary. The quaternary ammonium typed ionic liquid of 1-allyl-methylimidazolium chloride, 4-vinylbiphenyl and ethylene dimethacrylate were co-polymerized and in situ grown on the surface of cotton thread as extraction phase. The SPME tube showed excellent performance for the extraction of three non-steroidal anti-inflammatory drugs including ketoprofen, naproxen and flurbiprofen due to the strong ion exchange and hydrophobic interactions. After online coupling with HPLC system by six-port valve, the method was applied for the quantitative analysis of non-steroidal anti-inflammatory drugs in human plasma samples showing good enrichment performance (enrichment factor between 263-279), high sensitivity, good linearity and good reproducibility. This article is protected by copyright. All rights reserved.