A nanocomposite/crude extract enzyme-based xanthine biosensor.
A novel amperometric biosensor for xanthine was developed based on covalent immobilization of crude xanthine oxidase (XOD) extracted from bovine milk onto a hybrid nanocomposite film via glutaraldehyde. Toward the preparation of the film, a stable colloids solution of core-shell Fe3O4/polyaniline nanoparticles (PANI/Fe3O4 NPs) was dispersed in solution containing chitosan (CHT) and H2PtCl6 and electrodeposited over the surface of a carbon paste electrode (CPE) in one step. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectrophotometry, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were used for characterization of the electrode surface. The developed biosensor (XOD/CHT/Pt NPs/PANI/Fe3O4/CPE) was employed for determination of xanthine based on amperometric detection of hydrogen peroxide (H2O2) reduction at -0.35V (vs. Ag/AgCl). The biosensor exhibited a fast response time to xanthine within 8s and a linear working concentration range from 0.2 to 36.0μM (R(2)=0.997) with a detection limit of 0.1μM (signal/noise [S/N]=3). The sensitivity of the biosensor was 13.58μAμM(-1)cm(-2). The apparent Michaelis-Menten (Km) value for xanthine was found to be 4.7μM. The fabricated biosensor was successfully applied for measurement of fish and chicken meat freshness, which was in agreement with the standard method at the 95% confidence level.
['Sadeghi|Susan|S|', 'Fooladi|Ebrahim|E|', 'Malekaneh|Mohammad|M|']
D015374:Biosensing Techniques D058266:Dielectric Spectroscopy D004800:Enzymes, Immobilized D057230:Limit of Detection D008855:Microscopy, Electron, Scanning D053761:Nanocomposites D017550:Spectroscopy, Fourier Transform Infrared D019820:Xanthine D014969:Xanthine Oxidase
Xanthine Biosensor Crude xanthine oxidase Hybrid nanocomposite film Fe(3)O(4)/polyaniline core–shell