An improved microfluidic device to enhance the enrichment factors in liquid phase microextraction: application to the simultaneous extraction of polar and non-polar acids in biological samples

Exploring the impact of polyvinylidenefluoride membrane physical properties on the enrichment efficacy of microfluidic electro-membrane extraction of acidic drugs

Membrane technology has revolutionized various fields with its energy efficiency, versatility, user-friendliness, and adaptability. This study introduces a microfluidic chip, comprised of silicone rubber and polymethylmethacrylate (PMMA) sheets to explore the impacts of polymeric support morphology on electro-membrane extraction efficiency, representing a pioneering exploration in this field. In this research, three polyvinylidenefluoride (PVDF) membranes with distinct pore sizes were fabricated and their characteristics were assessed through field-emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM). This investigation centers on the extraction of three widely prescribed non-steroidal anti-inflammatory drugs: aspirin (ASA), naproxen (NAP), and ibuprofen (IBU). Quantitative parameters in the extraction process including voltage, donor phase flow rate, and acceptor phase composition were optimized, considering the type of membrane as a qualitative factor. To assess the performance of the fabricated PVDF membranes, a comparative analysis with a commercially available Polypropylene (PP) membrane was conducted. Efficient enrichment factors of 30.86, 23.15, and 21.06 were attained for ASA, NAP, and IBU, respectively, from urine samples under optimal conditions using the optimum PVDF membrane. Significantly, the choice of the ideal membrane amplified the purification levels of ASA, NAP, and IBU by factors of 1.6, 7.5, and 40, respectively.

ZIF67-derived porous carbon-reinforced electrospun nanofiber as an extractive phase for on-chip micro-solid-phase extraction of antifungals from biological fluids prior to liquid chromatography tandem mass spectrometry

With a view to improving applicability as a sorbent while overcoming the challenges associated with its powdery nature, cobalt-doped zeolitic imidazolate framework (ZIF 67)-derived nanoporous carbon (Co-NPC) was employed as an additive in nanofiber through the process of electrospinning. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Brunauer-Emmett-Teller (BET) surface area analysis were used to characterize the resulting nanocomposite. A microfluidic chip device with four layers, including two layers entailing spiral channels, was designed and employed to assess the analytical performance of the fabricated Co-NPC-reinforced electrospun composite. To do so, a folded piece of electrospun composite was sandwiched between two layers with spiral channels. Therefore, both sides of the folded composite acted as a sorptive phase to extract antifungal drugs as target analytes. The significant factors affecting the efficiency of the extraction process were investigated and optimized. Subsequently, the technique was verified through the utilization of liquid chromatography-tandem mass spectrometry (LC-MS/MS) by employing optimal parameters. The optimal conditions were applied to evaluate the figures of merit. A linear range was obtained for antifungal drugs within the range 0.25-200.0 ng ml-1 with an R2 value of ≥ 0.9914. The method demonstrated detection limits ranging between 0.08 and 0.40 ng ml-1. The intra-day and inter-day precisions were less than 6.9%. Relative recoveries exhibited variations between 91.4-106.8%, 95.9-103.6%, and 96.4-109.3% for ketoconazole, clotrimazole, and miconazole, respectively. The proposed approach yielded satisfactory results, demonstrating its efficiency.