[Determination of 2,4-D using disposable amperometric immunosensor]

2,4-Dichlorophenoxyacetic Acid (2,4-D) is the herbicide widely applied in the world. An amperometric immunosensor to detect 2,4-D was described. Firstly, 2,4-D-protein conjugate was prepared using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). The rabbit antiserum was prepared with substitution degree of 16. Secondly, the immunosensor was fabricated using screen printing technique. The 2,4-D/PLL conjugate was immobilized on the surface of screen printed carbon electrode via crosslinking method. The free and immobilized 2,4-D competed the binding sites of anti-2,4-D antiserum. After HRP-labeled goat-anti-rabbit IgG binding with anti-2,4 antiserum, the substrate was added and current response was recorded. The dependency of concentration of antiserum and HRP-labeled anti-IgG on current response was also studied. The result shows that limit of detection for 2,4-D is 1. 69 ng/mL with linear range 1.69 - 30000 ng/mL, which reveal the potential ability to evaluate the safety of drinking