Electrochemical sensor for 2,4-dichlorophenoxy acetic acid using molecularly imprinted polypyrrole membrane as recognition element

An electrochemical sensor based on molecularly imprinted polypyrrole membranes is reported for the determination of 2,4-dichlorophenoxy acetic acid (2,4-D). The sensor was prepared by electropolymerization of pyrrole on a glassy carbon electrode in the presence of 2,4-D as a template. The template was removed by overoxidation at +1.3 V in buffer solution. The sensor can effectively improve the reductive properties of 2,4-D and eliminate interferences by other pesticides and electroactive species. The peak current at -0.78 V is linear with the concentration of 2,4-D from 1.0 to 10 A mu M, the detection limit is 0.83 A mu M (at 3 sigma), and the relative standard deviation is 3.9% (at 5.0 A mu M of 2,4-D; n = 7). The method has been successfully applied to the determination of 2,4-D in environmental water samples, with recovery rates ranging from 92% to 108%.