基于抑制作用的新型葡萄糖氧化酶传感器测定环境污染物汞离子的研究

Study on the Determination of Environmentally Pollutional Mercury Using a Novel Inhibition-Based Glucose Oxidase Sensor

本文提出了一种基于抑制作用的新型葡萄糖氧化酶生物传感器用于测定环境样品中二价汞离子。其工作原理是汞离子对电极上葡萄糖氧化酶分子的抑制作用引起响应电流的下降而产生一可测定信号。详细探讨了电极的氧化还原反应机理及测试性能。该传感器对汞离子的检出限是0.49 ng/mL,抑制率和汞离子浓度的自然对数值在0.49~783.21 ng/mL和783.21 ng/mL^25.55μg/mL范围内分别呈良好的线性关系。酶电极在抑制后可以完全恢复活性。考察了铅(Ⅱ)、铜(Ⅱ)、镉(Ⅱ) 和铬(Ⅲ)离子对汞离子测定的干扰。测定了汞离子在土壤浸出液中的回收率,结果良好。

A novel inhibition-based biosensor of glucose oxidase (GOx) for environmental mercury detection is described. The response of the sensor is based on the current reduction in the electrochemical system by inhibition of mercury against GOx electrode. The mechanism of the redox reaction on the electrode,and the performance of the sensor are studied. The detection limit of the inhibition-based sensor towards mercury is 0.49 ng/mL. The linear response range is divided into two parts,one is 0.49~783.21 ng/mL,and the other is 783.21 ng/mL^25.55 μg/mL. The Pt/PA/Fc/GA/GOx membrane can be completely reactivated after inhibition,and remains 70% activity in more than one month. Interference to mercury determination from lead(Ⅱ),copper(Ⅱ),cadmium(Ⅱ) and chromium(Ⅲ) is found to be ignorable. The sensor has been used for mercury determination in soil extract with good results.