Sadeghi Susan, Fooladi Ebrahim, Malekaneh Mohammad
Department of Chemistry, Faculty of Science, University of Birjand, Birjand, South Khorasan, Iran.
Department of Chemistry, Faculty of Science, University of Birjand, Birjand, South Khorasan, Iran.
Anal Biochem. 2014 Nov 1;464:51-9. doi: 10.1016/j.ab.2014.07.013. Epub 2014 Jul 22.
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.
基于通过戊二醛将从牛奶中提取的粗制黄嘌呤氧化酶（XOD）共价固定在混合纳米复合膜上，开发了一种新型的黄嘌呤安培生物传感器。在制备该膜时，将核壳型Fe3O4/聚苯胺纳米颗粒（PANI/Fe3O4 NPs）的稳定胶体溶液分散在含有壳聚糖（CHT）和H2PtCl6的溶液中，并一步电沉积在碳糊电极（CPE）表面。使用扫描电子显微镜（SEM）、傅里叶变换红外（FTIR）光谱法、循环伏安法（CV）和电化学阻抗谱（EIS）对电极表面进行表征。所开发的生物传感器（XOD/CHT/Pt NPs/PANI/Fe3O4/CPE）用于基于在-0.35V（相对于Ag/AgCl）下对过氧化氢（H2O2）还原的安培检测来测定黄嘌呤。该生物传感器对黄嘌呤的响应时间在8秒内很快，线性工作浓度范围为0.2至36.0μM（R(2)=0.997），检测限为0.1μM（信号/噪声[S/N]=3）。该生物传感器的灵敏度为13.58μAμM(-1)cm(-2)。发现黄嘌呤的表观米氏（Km）值为4.7μM。所制备的生物传感器成功应用于鱼肉和鸡肉新鲜度的测量，在95%置信水平下与标准方法一致。
