A novel sensor based on nanobiocomposite Au--In₂O₃--chitosan modified acetylene black paste electrode for sensitive detection of antimycotic ciclopirox olamine

For the first time, a sensitive conductive nanobiocomposite sensor consisting of Au-In₂O₃ nanocomposite and chitosan (CS) was successfully prepared and used for the modification of acetylene black paste electrode (Au--In₂O₃--CS/ABPE). The phase structures, composition and morphology of Au-In₂O₃ nanocomposite were characterized by X-ray diffraction (XRD), energy-dispersed X-ray (EDX) and transmission electron microscopy (TEM). Electrochemical activities and surface analysis of the biosensor electrode Au--In₂O₃--CS/ABPE were investigated using scanning electron microscopy (SEM), cyclic voltammetry and square wave voltammetry. The modified electrode showed an excellent electrochemical activity toward the electro-oxidation of the antimycotic ciclopirox olamine (CPX) leading to a significant improvement in sensitivity as compared to the bare ABPE. The proposed biosensor demonstrated linearity in the range 0.199 - 16.22µmolL^-1, with high sensitivity (64.57μAµmolL^-1cm^-2) and detection limit of 6.64 × 10^-9molL^-1 CPX. The analytical performance of this biosensor was evaluated for detection of CPX in pharmaceutical formulations with good accuracy and precision. This proposed method was validated by UPLC and the results are in agreement at the 95% confidence level.