A miniaturized system of anion exchange solid phase extraction (SPE) based on a screen-printed electrode was developed as a point of care (POC) device for extraction and quantitative determination of anionic analytes. Nylon 6/polyaniline nanofibers were fabricated by electrospinning and in-situ oxidative polymerization techniques coated on a screen-printed working electrode and characterized by Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) methods. The effects of essential parameters such as desorption conditions, pH of the sample solution, adsorption voltage, adsorption time, and salt concentration on the performance of the method were investigated. To evaluate the performance of the system, angiotensin ΙΙ receptor antagonists, including valsartan, losartan, and irbesartan, were selected as model compounds and analyzed by HPLC/UV after extraction. The limits of detection and quantification were ranging between 0.4 and 0.9 μg L-1 and 1.3-3.0 μg L-1, respectively. The linear dynamic range for Losartan, Irbesartan, and Valsartan was 2-400, 4-1000, and 2-400 μg L-1, respectively, with R2 > 0.991. Finally, the method was applied for the determination of ARA-IIs in human blood plasma samples, and relative recoveries in the range of 89.0-107.8% with relative standard deviation (RSDs (≤8.9% were obtained.
Keywords: Angiotensin ΙΙ receptor antagonists; Ion exchange solid phase extraction; Nanofibers; Nylon 6/polyaniline; Screen-printed electrode.
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