Concurrent analysis of six NSAIDs in human plasma using polyurethane/B–N–S-co-doped rGO nanofiber-modified glassy carbon electrode followed by EA-SPME

Herein, a novel voltammetric biosensor was designed and constructed for the simultaneous measurement of six nonsteroidal anti-inflammatory drugs (NSAIDs), including celecoxib, mefenamic acid, acetaminophen, naproxen, ibuprofen, and caffeine. In this biosensor, the glassy carbon electrode (GCE) was used as an unmodified working electrode. For modification, the water based-polyurethane-(B-N-S)-co doped-rGO electrospun nanofibers (WB-PU-(B-N-S)-rGO NFs) were first collected on the conductive surface of GCE. Subsequently, the biosensor was used to analyze the presence of six NSAIDs in human plasma samples. Prior to this analysis, the plasma samples were prepared using electrospun nanofibers made of polyvinyl alcohol/casein/tannic acid/polyaniline/titanium dioxide nanoparticles (PVA/CAS/TA/PANI/TiO₂ NPs) in electrically assisted solid phase microextraction (EA-SPME) on a pewter rod. The WB-PU-(B-N-S)-rGO NFs were characterized with Fourier transform-infrared (FT-IR), field emission-scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy with elemental mapping analysis (EDS-Mapping), and X-ray diffraction (XRD), which confirmed the synthesis of this nanocomposite. According to optimum conditions, the wide linear range was 30-900 μM with <i>R</i>² ≥ 0.9585, and low detection limits ranged from 8.6 to 47.5 μM based on S/N = 3. The intra-day and inter-day RSDs% were obtained within 4.17-4.90% and 4.92-5.49%, respectively. Finally, the efficiency of the electrochemical biosensor was evaluated to determine these six NSAIDs in human plasma samples with good recoveries (91.0-102.8%).