In the present work, a disposable microextraction device with a polyamide 6 nano-fibrous supported liquid membrane (SLM) is employed for the pretreatment of minute volumes of biological fluids. The device is placed in a sample vial for an at-line coupling to a commercial capillary electrophoresis instrument with UV-Vis detection (CE-UV) and injections are performed fully automatically from the free acceptor solution above the SLM with no contact between the capillary and the membrane. Up to 4-fold enrichment of model basic (nortriptyline, haloperidol, loperamide, and papaverine) and acidic (ibuprofen, naproxen, ketoprofen, and diclofenac) drugs is achieved by optimizing the ratio of the donor to the acceptor solution volumes (16 to 4 μL, respectively). The actual setup enables SLM extractions from less than a drop of sample and is suitable for pretreatment of scarce human body fluids. Two unique methods are reported for efficient clean-up and enrichment of the basic and acidic drugs from capillary blood (formed as dried blood spot), serum, and urine samples, which enable their determination at therapeutic and/or toxic levels. The hyphenation of the SLM extraction with CE-UV analysis provides good repeatability (RSD, 2.4-14.9%), linearity (r2, 0.988-1.000), sensitivity (LOD, 0.017-0.22 mg L-1), and extraction recovery (ER, 20-106%) at short extraction times (10 min) and with minimum consumption of samples and reagents. Graphical abstract.

Department of Analytical Chemistry Faculty of Chemistry University of Seville Profesor Garcia González s n 41012 Seville Spain

Institute of Analytical Chemistry of the Czech Academy of Sciences Veveří 97 60200 Brno Czech Republic

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