Low-Level Quantification of Cefixime and Cefdinir in Human Plasma Using Ultrasound-and Magnetic-Assisted Dispersive Micro-Solid-Phase Extraction (MSPE) Based upon Carbon Quantum Dots (CQDs) Functionalized with Magnetite/Zeolitic Imidazolate Framework 71/Polypyrrole Combined with High-Performance Liquid Chromatography (HPLC)

A promising and reusable nanohybrid based on carbon quantum dots immobilized with Fe3O4/zeolitic imidazolate framework-71/polypyrrole (CQD/Fe3O4/ZIF-71/PPy) was fabricated as a sorbent for ultrasound-and magnetic-assisted dispersive micro-solid-phase extraction (US-M-A-DMSPE) followed by high-performance liquid chromatography with ultraviolet detection (HPLC-UV) for simultaneous trace determination of cefixime (CFX) and cefdinir (CFD) in human plasma. In order to improve the contact between the analyte and the sorbent, the surface of the CQDs was modified by individual materials involving zeolitic imidazolate framework and polypyrrole via an in-situ synthesis of ZIF-71 followed by oxidative polymerization of pyrrole. The structure of the prepared sorbent was characterized by x-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Under the optimized conditions, the nanosorbent provided high adsorption and selectivity toward the analytes. The limits of detection for CFX and CFD were 0.15 and 0.04 ng mL−1, respectively. The coefficients of determination (r2) were between 0.990 and 0.993, with dynamic ranges of 0.5–1750.0 and 0.2–1500.0 ng mL−1. The method was used for quantifying CFX and CFD in plasma samples to evaluate the pharmacokinetic aspects, including the half-life (T½), the time to reach the maximum concentration (Tmax), the maximum plasma concentration (Cmax), area under the curve (AUC0-24) and area under the curve at infinite time (AUC0-∞). Reliable reproducibility as the intra- assay (≤ 6.3%) and inter-assay (≤ 8.7%) together with reasonable accuracy (≤ 8.8%) were obtained. [ABSTRACT FROM AUTHOR]