Polyacrylonitrile nanofibers/ Ni0.5Zn0.5Fe2O4 nanocomposite as a modifier in carbon paste electrode for selective and sensitive determination of sunitinib in biological samples

Due to the importance of drugs determination in pharmaceuticals for quality control in pharmacopeia, many routine analytical methods such as HPLC have been developed. But, these methods suffer from some disadvantages such as time-consuming, expensive, and need to labor operators. Among various analytical methods, electroanalytical methods are rapid, inexpensive and easy to operation [1, 2].In the present work, a novel modifier, polyacrylonitrile nanofibers/Ni0.5Zn0.5Fe2O4, for carbon paste electrode has been synthesized using a simple electrospinning method. The synthesized nanocomposite was fully characterized using methods such as Fourier transform infrared spectroscopy, scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. Preliminary experiments showed that the nanocomposite had an electro-catalytic effect on the electro-oxidation of sunitinib and a significant improvement in the drug anodic current was obtained at +0.665 V (vs. Ag/AgCl). Various chemical parameters and instrumental parameters which could potentially affect the electrochemical signal were optimized. Under the optimum conditions, the analytical figures of merit were extracted and the method was fully validated. A relatively wide dynamic linear range of 0.018-18.77 µM with a detection limit of 0.9 nM was obtained. Furthermore, the method was applied for the determination sunitinib in biological fluids such as human serum samples with acceptable recoveries and minimal matrix effect. A comparison of figures of merit between the developed method and other previously developed methods showed that a powerful alternative method for the determination of sunitinib in biological samples has been developed.