基于壳聚糖/SiO_2杂化膜固定酪氨酸酶生物传感器测定水中苯酚

Determination of phenol in water by a tyrosinase biosensor based on chitosan/SiO_2 hybrid film immobilization

用壳聚糖/SiO2杂化膜对酪氨酸酶进行固定,制备基于多壁碳纳米管修饰玻碳电极的苯酚传感器,研究其对苯酚的响应,并对溶液的pH值与工作电压等测定参数进行优化。苯酚等酚类化合物可通过酶催化产生的醌在-100 mV直接还原而测定。该传感器达到95%稳定状态电流的时间在10 s以内,测定苯酚的线性响应范围为1.0×10-8～1.5×10-4mol/L,检出限为4.0×10-9mol/L,米氏常数(Kampp)为5.78×10-6mol/L,对1.0×10-6mol/L苯酚平行测定8次的RSD为3.2%,使用三周后活性仍保持原有活性的75%。将该生物传感器用于实际水样中苯酚含量检测,回收率为93%～104%。

Tyrosinase was immobilized by chitosan/SiO2 hybrid film to prepare phenol sensor based on multi-wall carbon nanotube（MWCNT） modified glassy carbon electrode（GCE）.The response of the sensor to phenol was studied.The determination parameters including pH of solution and operating potential were optimized.Phenolic compounds could be determined by the direct reduction of quinone generated by enzyme catalysis at-100 mV.The sensor could reach 95 % of steady-state current within 10 s,and it showed a linear response to phenol in the range of 1.0×10^-8 to 1.5×10^-4 mol/L.The detection limit was 4.0×10^-9 mol/L,the apparent Michaelis-Menten constant（Kappm） was 5.78×10^-6 mol/L,and the relative standard deviation（RSD） for 1.0×10^-6 mol/L phenol was 3.2 %（n=8）.The sensor response retained 75 % of initial value after 3 weeks.The proposed method has been applied to the determination of phenol in real water samples,and the recoveries were between 93 % and 104 %.