印迹零流电位法测定邻甲氧基苯胺

Determination of o-methoxyaniline by imprinted zero current potentiometry

邻甲氧基苯胺是一种潜在致癌芳香胺,建立检测其含量的灵敏快捷方法对日常环境监测非常重要.以邻甲氧基苯胺(o-methoxyaniline,OMA)为模板分子,丙烯酰胺为功能单体,通过电聚合方法合成邻甲氧基苯胺印迹聚合物(o-methoxyaniline molecularly imprinted polymer,OMA-MIP),并以零流电位法优化合成参数,制备出具有灵敏零流电位响应的OMA-MIP零流电位法印迹传感器.与其他结构相近物质如对氨基偶氮苯、4-氯苯胺、邻甲苯胺、邻联甲苯胺、联苯胺和胭脂红相比,所制备的OMA-MIP双极制界面电位传感器对OMA印迹吸附容量最大,选择性最好;且对浓度为0. 001～50. 000μmol/L的OMA具有良好的线性响应,检测限达0. 640 nmol/L. 5个传感器测定10. 000 nmol/L的OMA,零流电位的相对标准偏差为1. 45%,表明传感器重现性好;用同一个传感器每隔2 d测定同一浓度的OMA,连测10次的相对标准偏差为0. 95%,说明传感器的稳定性好.在误差范围±5%内,与OMA结构相近的有机物及可能共存的某些金属阳离子不干扰测定.基于零流电位法与分子印迹技术制备出的OMA-MIP传感器可用于实际样品测定,回收率为95. 20%～105. 72%.

O-methoxyaniline( OMA-MIP) is a potential carcinogenic aromatic amine. It is very important to establish a sensitive and fast method for daily environmental monitoring of o-methoxyaniline. The o-methoxyaniline molecularly imprinted polymer is synthesized by electropolymerization using OMA as template molecule and acrylamide as functional monomer. The interfacial potentiometry with double poles is utilized to optimize the synthetic parameters,and the OMA-MIP bipolar interface potential sensor with sensitive zero current response is prepared. By comparison with other substances such as 4-aminoazobenzene,p-chloroaniline,o-toluidine,o-tolidine,benzidine and carmine, as-prepared OMA-MIP sensor presents the largest imprinting adsorption capacity and the best selectivity of OMA,which has a good linear response to OMA concentration in the range from 0. 001 μmol/L to50. 000 μmol/L with 0. 640 nmol/L detection limit. OMA of 10. 000 nmol/L is measured by 5 sensors and the relative standard deviation of the zero current potential is 1. 45%,indicating the good reproducibility of this sensor.OMA with identical concentration is measured using the same sensor for 10 successive measurements every 2 d with the relative standard deviation of 0. 95%,indicating that the sensor has good stability. Within the error range from-5% to 5%. Organic matter similar to OMA structure and some metal cations that may coexist do not interfere with the determination. The OMA-MIP sensor prepared by bipolar interfacial potentiometry and molecular imprinting technique can be used to determine the concentration of OMA in real samples with the recoveries from 95. 20% to105. 72%.