Immunosensor for 2,4-dichlorophenoxyacetic acid in aqueous/organic solvent soil extracts.
The development of a simple electrochemical immunoassay procedure for the field-based quantification of the herbicide 2,4-D in methanolic soil extracts is presented. The sensor utilizes a competitive immunoassay format incorporating an immobilized antigen complex at the surface of a disposable screen-printed working electrode element. The extent of glucose oxidase-labeled antibody binding to the antigen--electrode is determined amperometrically and is related to sample analyte concentration. The performance of the sensor is assessed in buffer, 30% methanol, and methanolic soil extracts. The device is capable of quantifying 2,4-D in all three matrixes at the low ppm level with coefficient of variation values of 6.2-33.6%. The causes of the variation observed in the sensor response in different soil matrixes are examined and improvements proposed. The sensor, tested in parallel with a commercial 2,4-D immunoassay test kit, yields comparable quantitative data and detection limits while exhibiting greater assay simplicity.
Kröger
S
S
Cranfield Biotechnology Centre, Cranfield University, Bedfordshire, U.K.
Setford
S J
SJ
Turner
A P
AP
D015084:2,4-Dichlorophenoxyacetic Acid / Q000032:analysis*; D005949:Glucose Oxidase / Q000378:metabolism; D007118:Immunoassay; D007202:Indicators and Reagents; D000432:Methanol; D012987:Soil / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D012997:Solvents
D007202:Indicators and Reagents; D012987:Soil; D012989:Soil Pollutants; D012997:Solvents; D015084:2,4-Dichlorophenoxyacetic Acid; D005949:Glucose Oxidase; D000432:Methanol