原位制备纳米功能化金电极快速检测牛奶中的微生物

在0.1 mol/L磷酸盐缓冲溶液(PBS,pH 7.0)中,于2.0V恒电位电解10 min,即可在金电极表面原位、快速制备纳米功能化修饰膜.经原子力显微镜表征,此修饰膜具有纳米尺度的蓬松结构.此纳米金膜对细胞膜上脂质过氧化反应具有显著的催化作用,因而对细菌产生电流响应.采用传统的标准平板计数法对试样进行细菌培养计数作为校正,以计时电流法电流响应作为输出信号进行细菌的测定,响应电流和细菌数量呈线性关系,据此可对牛奶样品中细菌浓度进行快速测定.本方法的测定范围为1.1×103～2.5×107 cfu/mL,检测时间缩短至1h以内,较平板计数法有显著改善.

Rapid Detection of Microorganisms in Milk Using an In-situ Prepared Nano-functionalized Gold Electrode

An in-situ,facile and rapid method was developed to prepare a nano-functionalized gold electrode.By the electrolysis under applied potential of +2 V in PBS of pH 7.0 for 10 min,a rough nano-porous film formed on the surface of a polished gold plate electrode.This novel nano-functiona-lized gold electrode could be applied for rapid detection of bacteria quantity in milk.The detection was based on the catalysis of lipid peroxidation on cell membrane of bacteria by the nano-porous Au film.The response of the current in chronoamperometry would linearly respond the bacterial content in milk which was calibrated by the national standard method(Standard plate count method).Therefore the accurate quantity of bacteria was attained from the current response on prepared electrode.The results showed that the target bacteria could be detected at a content range from 1.1×103 cfu/mL to 2.5×107 cfu/mL.The whole process of the detection could be completed within 1 h.