基于自组装电化学免疫传感器对污泥中PCB77的检测

构建了一种基于L-半胱氨酸、壳聚糖、戊二醛和纳米金层层自组装技术的新型无标记、高灵敏电流型免疫传感器,并用于检测3,3’,4,4’-四氯联苯(PCB77).利用示差脉冲法研究了修饰电极表面的电化学特性以及测试溶液的pH值、孵育时间和温度对免疫传感器性能的影响.实验结果表明,该免疫传感器在含不同浓度PCB77的磷酸盐缓冲溶液(PBS,pH=7.4)中于35℃下孵育30 min后,在含有5 mmol/L K3Fe(CN)6/K4Fe(CN)6(摩尔比1∶1)和0.1 mol/L KCl的PBS溶液(pH=6.0)中测定,响应电流与PCB77浓度在0.1～160 ng/mL范围内呈良好的线性关系,R=0.9964,检出限为0.01 ng/mL.该传感器制备简单、灵敏度高、稳定性好,可以重复使用.将其用于检测实际污泥样品中的PCB77,回收率为95%～112%.

Amperometric Immunosensor Based on Layer-by-layer Assembly for Detecting PCB77 in Sludge Samples

A new type of amperometric immunosensor for the determination of PCB77 was reported. Gold nanoparticles, glutaraldehyde and chitosan were assembled layer-by-layer into films on the gold electrode modified by L-cysteine for fabrication of the immunosensor. The preparation procedure of the sensor was characterized and the operation conditions, such as the pH value of supporting solution, incubated temperature and time were studied by differential pulse voltammetry. Under the optimized working conditions, the current response of the immunosensor was proportional to the concentration of naphthalene in the range of 0.1—160 ng/mL with a detection limit of 0.01 ng/mL(R=0.9964) . This method was applied to the PCB77 detection in sludge samples and the recovery was ranging in 95.0%—112.5%. The reported immunosensor exhibited high sensitivity and long-term stability for PCB77 detection, and was easy to be prepared and regenerated.