检测2,4-D的一次性安培型免疫传感器

2,4-D是广泛使用的除草剂,以2,4-D为检测目标,研究了安培型免疫传感器.首先采用1-乙基-3-(3-二甲基氨丙基)碳二亚胺盐酸盐(EDC)作为交联剂制备2,4-D与BSA以及PLL的偶联物.用结合比1∶16的2,4-D与偶联物制备兔抗血清.免疫传感器的制备包括2个步骤,使用丝网印刷工艺制备一次性碳电极,然后通过戊二醛交联在电极表面固定2,4-D与多聚赖氨酸(PLL)的偶联物.待测水样与2,4-D抗血清和HRP酶标二抗进行间接免疫竞争反应.在HRP酶在邻苯二胺和H₂O₂的共同作用下发生酶促反应,检测还原电流以反映2,4-D的浓度.试验了不同浓度抗血清和酶标二抗对检测信号的影响,结果表明,2,4-D的检测下限达到1.69ng/mL,线性区间1.69～30 000ng/mL,适合饮用水中2,4-D的检测要求.

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