A New Amperometric Benzaldhyde Biosensor Based on Aldehyde Oxidase Immobilized on Fe₃O₄‐GrapheneOxide/Polyvinylpyrrolidone/Polyaniline Nanocomposite

Abstract

Abstract A new biosensor for determination of benzaldehyde based on carbon past electrode (CPE) modified with a Fe 3 O 4 ‐graphen oxide/polyvinyl pyrrolidone/polyaniline (Fe 3 O 4 /GO/PVP/PANI) nanocomposite was developed. The nanocomposite was electrodeposited on the surface of CPE using cyclic voltammetry technique. The crude extract aldehyde (AOX) oxidase enzyme isolated from rat liver was immobilized on the Fe 3 O 4 /GO/PVP/PANI nanocomposite and the prepared biosensor was employed for benzaldehyde oxidation to H 2 O 2 . The benzaldhyde measured amperometrically based on reduction of produced H 2 O 2 at −0.25 V(vs. Ag/AgCl). The cyclic voltammetry and electrochemical impedance spectroscopy studies of the modified electrode indicated that Fe 3 O 4 /GO has an excellent electrocatalytic activity and can be used as an electron mediator for H 2 O 2 reduction. The presence of PVP in the nanocomposite could substantially improve the dispersibility of GO, leading to enhanced sensitivity of the biosensor. Under optimum conditions, the biosensor exhibited a fast response time to benzaldhyde within 10 s. The sensor showed a linear response to benzaldehyde concentration in the range of 0.5–50 µM with a limit of detection of 0.4 µM( S / N =3) and sensitivity of 4.173 µA µM −1 cm −2 . The biosensor revealed a preference for benzldehyde than studied aliphatic aldehydes. The new biosensor showed good performance to analysis of benzaldhyde in drugs injection formulations.