Extraction of thymoquinone from blackseed with electrospun nanofibers as a new method and detection of it with electrochemical biosensor

Thymoquinone is the main constituent of blackseed and it has effects on the treatment of many illnesses such as kidney diseases [۱]. Because of thymoquinone advantages, First, new electrospun۳nanofibers with polyvinyl chloride/ethylene vinyl acetate Latex /Electrochemically (reduced graphene oxide/polypyrrole)/Silybum marianum inflorescence extract (PVC/EVA/(rGO/Ppy)/SM) was prepared, and then thymoquinone was extracted from Nigella Sativa with these nanofibers. Finally, detection of Thymoquinone was done with the construction of a simple nonenzymatic electrochemical biosensor with using the Copper (II) oxide nanoparticles/reduced graphene oxide/glassy carbon electrode (CuO/rGO/GCE). The ot rGO has large surface area [۲] and strong mechanical properties. Other electrochemical methods for studing of the TQ need to more time [۳]. The effective conditions on TQ adsorption and desorption were optimized by Design-Expert ۱۲.۰ software and one at time method, respectively. Also, time and potential values that were effect on constructed biosensor were optimized by both Design-Expert ۱۲.۰ and one at time methods and the comparison between two methods was done. So the optimized factors are: time of reduction of GO to rGO = ۱۲۰ s, Cu deposition potential and time = -۰.۲۵ V and ۲۵۰ s, respectively. The morphology of PVC/EVA/(rGO/Ppy)/SM nanofibers and nanocomposites that was used for electrode modification were characterized by field emission scanning electron microscopy and EDAX-elemental mapping analysis. The structure characterization of electrospun nanofibers was done by Fourier transforms - infrared (FT-IR) Spectrometer, X-ray diffraction (XRD), and thermogravimetry analysis (TGA). Also, the nanocomposite structure was investigated by Raman spectroscopy, XRD, ultraviolet-visible (UV-vis) spectroscopy, and FTIR. The conductivity of GCE and GCE/rGO/CuO electrode surfaces was compared with electrochemical impedance spectroscopy (EIS). Finally, the electrochemical biosensor was put into human blood serum samples and the standard addition method was done with the addition of TQ standard solution to them. The linear range and detection limit was reached ۵۰-۱۰۰۰ μM and ۴.۸۵ μM, respectively (S/N=۳).