title: Label-free impedimetric immunosensor for sensitive detection of 2,4-dichlorophenoxybutyric acid (2,4-DB) in soybean.
abstract: Electrochemical impedance immunosensor, with its high sensitivity from electrochemical impedance analysis and ideal specificity from the immunoassay, is increasingly used in the detection of a kind of phenoxy acid herbicides which is 2,4-Dichlorophenoxybutyric acid (2,4-DB). In this experiment, synthetic 2,4-DB antibodies were immobilized on the electrode by the crosslinking of L-Cysteine/glutaraldehyde, and 2,4-DB were measured by the increase of electron-transfer resistance when the immune reaction occurred, with Fe(CN)(6)(3-)/Fe(CN)(6)(4-) as the probe. Under optimal conditions, the change of resistance is in a linear relationship with the logarithm of the concentration in the range of 1.0×10(-7)-1.0×10(-3) g/L (R=0.994) with the detection limit of 1.0×10(-7) g/L (0.1 ppb). This method bears such merits as simplicity in operation, high sensitivity, wide linear range, specificity, reproducibility and good stability. The actual soybean samples were analyzed with the recovery of 82.8%-102.3%.
authors.affiliation: College of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of environmental engineering and monitoring, Yangzhou University, 180 Si-Wang-Ting Road, Yangzhou 225002, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Meirong
authors.initials: M
authors.lastname: Wang
authors.forename: Chengyin
authors.initials: C
authors.lastname: Wang
authors.forename: Xiaoya
authors.initials: X
authors.lastname: Hu
authors.forename: Guoxiu
authors.initials: G
authors.lastname: Wang
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000031:analogs & derivatives* / Q000032:analysis; D015374:Biosensing Techniques; D015203:Reproducibility of Results; D013025:Glycine max / Q000737:chemistry*
chemical_list: D015084:2,4-Dichlorophenoxyacetic Acid; C004764:4-(2,4-dichlorophenoxy)butyric acid