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| 2, 4-Dichlorophenoxyacetic Acid (2,4-D), a widely used chemical in agriculture, is one of the main varieties of herbicides, but its biosafety risks become a new focus issue of human security. Traditional determination methods can not meet demand of food quality supervision and inspection because of their limitations. In this paper, a reagentless electrochemical impedance immunosensor for dichlorophenoxyacetic acid detection was developed based on the directly adsorbed anti- 2,4-D antibody on a porous nano-gold film when it was immobilized onto the porous nano-gold through electrostatic adsorption and covalently conjugation. The electrochemical impedance spectroscopy (EIS) was used to characterized the successful construction of the porous nano-gold film and the stepwise modifacation of the glassy-carbon electrode. As the interfacial electron transfer decreased, the impedance sigsenal would increase. The above results showed that the constructed electrode had good linearity with the 2,4-D content ranging of 0.5 ng/mL-5000 ng/mL and the linear equation is y = 0.045x + 62.55, and the correlation coefficient R is 0.9970, with a detection limit at about 0.1 ng/mL. It can directly obtained information through the impedance changes with the 2,4-D concentration. The results were consistently comparing with the results of HPLC which provides a new ways for detection of 2,4-D. |
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| Keywords:Botany; Impedance immunosensor; 2,4 - Dichlorophenoxyacetic Acid; Porous nano-gold |
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