A promising and reusable nanohybrid based on carbon quantum dots (CQD) 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 cephalosporins (Cefdinir & Cefixime) in human plasma. The structure of the prepared sorbent was characterized by x-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Under the optimized conditions, the nanosorbent provided high adsorption and selectivity toward the analytes. The limits of detection and the coefficients of determination (r2) with dynamic ranges for cefdinir & cefixime were estimated. The method was used for quantifying cefdinir & cefixime in plasma samples to evaluate the pharmacokinetic aspects,including the half-life (T1/2), 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 and inter-assay together with reasonable accuracy were obtained. Manuscript profile

In this search, an ultrasound-and magnetic-assisted dispersive micro-solid-phase extraction (US-M-A-DMSPE) was developed for selective separation of Pb ion by an innovative nanocomposite based on carbon quantum dots functionalized with magnetite/zeolitic imidazolate framework 71/polypyrrole. To fabricate the novel nanocomposite, first, the magnetized carbon quantum dot was functionalized by imidazolate zeolite-71, and then pyrrole was utilized as an oxidant agent in the chemical polymerization on the surface of magnetic carbon quantum dot functionalized with zeolitic imidazolate framework 71. Lead was analyzed by flam atomic absorption spectrometry (FAAS). The structure of nanosorbent was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray analyzer (EDX), vibrating sample magnetometry (VSM) and Fourier transform-infrared (FT-IR). To maximum recoveries of Pb (II), the optimum experimental conditions and analytical parameters such as amount of sorbent, pH of samples, ultrasonic time, chelating agent concentration, ionic strength, volume of desorbing solvent and reusability were estimated. Under the optimal conditions, the preconcentration factor was achieved 60. The limits of detection and quantification were found to be 0.15 ng mL−1 and 0.5 ng mL−1, respectively. The relative standard deviations (RSD%) of the developed US-M-A-DMSPE process is below was 2.9 %. The present process was successfully applied to the determination of Pb2+ ion at trace levels in water and food samples by ultrasound-and magnetic-assisted dispersive micro-solid-phase extraction tandem flame atomic adsorption spectroscopy (US-M-A-DMSPE-FAAS) and its validation was investigated by recovery experiments and analyzing certified reference material. Manuscript profile