Development of an immunoassay for the residues of the herbicide bensulfuron-methyl.
To develop a competitive indirect enzyme-linked immunosorbent assay based on polyclonal antibodies for the detection of the sulfonylurea herbicide bensulfuron-methyl, seven structurally related haptens were synthesized. Four of them mimicking the target analyte were conjugated to keyhole limpet hemocyanin by the N-hydroxysuccinimide activated ester method to use as immunogens, and all of them were conjugated to bovine serum albumin to use as plate-coating antigens. Polyclonal antibodies raised in rabbits and the coating antigens were screened and selected for the assay in simple homologous and heterologous ELISA formats. Three sensitive heterologous ELISAs were selected and optimized, showing the average IC(50) values of bensulfuron-methyl as low as 0.17, 0.09, and 0.09 ng/mL, the detection ranges of 0.04-0.60, 0.01-0.60, and 0.04-0.25 ng/mL, and the lowest detection limits of 0.03, 0.002, and 0.03 ng/mL, respectively. The cross-reactivities of other sulfonylurea herbicides and metabolites of bensulfuron-methyl to the antibodies were less than 15% in the two assays. Recoveries from the analyte-fortified water samples in assay I were in the range of 81-125% by simple dilution. The correlation between the ELISA and HPLC was 0.999 (n = 15) with a slope of 1.37 in the analysis of groundwater samples fortified with bensulfuron-methyl. The results obtained strongly indicate that the ELISA can be a highly sensitive and convenient tool for detecting bensulfuron-methyl residues in agricultural and environmental samples.
Lee
Jae Koo
JK
Department of Agricultural Chemistry, Chungbuk National University, Cheongju 361-763, Korea, and Bio-Organic Division, Korea. jklee@cbucc.chungbuk.ac.kr
Ahn
Ki Chang
KC
Park
Oee Sook
OS
Ko
Yong Kwan
YK
Kim
Dae-Whang
DW
D000818:Animals; D000917:Antibody Formation; D000918:Antibody Specificity; D000941:Antigens / Q000276:immunology; D002851:Chromatography, High Pressure Liquid; D003902:Detergents; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006241:Haptens / Q000737:chemistry / Q000276:immunology; D006433:Hemocyanins / Q000276:immunology; D006540:Herbicides / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007106:Immune Sera / Q000276:immunology; D007118:Immunoassay / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy; D009994:Osmolar Concentration; D010573:Pesticide Residues / Q000032:analysis*; D011817:Rabbits; D012680:Sensitivity and Specificity; D012997:Solvents; D013453:Sulfonylurea Compounds / Q000032:analysis* / Q000276:immunology
D000941:Antigens; D003902:Detergents; D006241:Haptens; D006540:Herbicides; D007106:Immune Sera; D010573:Pesticide Residues; D012997:Solvents; D013453:Sulfonylurea Compounds; C071475:methyl bensulfuron; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin