Acta Chimica Sinica ›› 2012, Vol. 70 ›› Issue (17): 1853-1857.DOI: 10.6023/A12050256 Previous Articles     Next Articles

Full Papers


李建平, 李玉平, 魏小平   

  1. 桂林理工大学化学与生物工程学院 桂林 541004
  • 投稿日期:2012-06-01 发布日期:2012-08-10
  • 通讯作者: 李建平
  • 基金资助:
    项目受国家自然科学基金(No. 21165007)和广西自然科学基金(No. 2012jjAA20076)资助.

Molecularly Imprinted Electrochemical Sensors Based on the Double-amplification from the Electro-catalysis of Poly-melamine and the Enzymatic Catalysis of HRP for Chlortoluron Determination

Li Jianping, Li Yuping, Wei Xiaoping   

  1. College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004
  • Received:2012-06-01 Published:2012-08-10
  • Supported by:
    Project supported by the National Natural Science Foundation of China (No. 21165007) and the Natural Science Foundation of Guangxi Province (No. 2012jjAA20076).

A molecular imprinted electrochemical sensor for the determination of the residue of chlortoluron (CH) in environment was prepared with melamine (MA) as functional monomer. The electropolymerization of poly-melamine-molecularly-imprinted-polymer (PMA-MIP) on the GC electrode was conducted in a 1.0 mol/L H2SO4 by cyclic voltammetry (CV) at room temperature (25 ℃). Then the template molecule (CH) on the PMA-MIP film was removed by nitric acid. The experimental conditions (including electrocatalysis of the MA film, pH effects, incubation and competition times) were optimized. The incubation time chosen for the subsequent experiments was 12 min and 12-min was also recommended as the optimized competition time. The Amperometric i-t curves were recorded during the determination. The detection of CH relied on a competition reaction between CH and horseradish peroxidase labeled chlortoluron (HRP-CH) coupled with the subsequent catalytic reduction of hydrogen peroxide by the poly-MA film. Highly sensitive detection of CH was achieved by the double amplification derived from the electro-catalysis of H2O2 on MA film and the enzymatic effect of HRP. There was linear relationship between the current changes and CH concentration in the range of 0.01~0.8 μmol/L with a detect limit of 2.64 nmol/L by chronoamperometric method. The proposed PMA-MIP sensor displayed excellent analytical performance (e.g., high sensitivity, good selectivity, and good reproducibility). Some analogues (difenoxuron, neburon, isoproturon and fluometuron) were also used as interferences to examine the selectivity. The changes in the current response of 94-time difenoxuron, 62-time neburon, 38-time fluometuron and 20-time isoproturon are negligible compared with chlortoluron. In addition, the feasibility of its practical applications has been demonstrated in the analysis of samples of tap water and soil extract solution. Recoveries were ranged from 97.0% to 107.0%, and the RSDs were less than 2%, which can be indicators of good recovery and practicability.

Key words: chlortoluron, molecularly imprinted electrochemical sensors, double amplification, poly-melamine, horseradish peroxidase (HRP)