Development of an ELISA for the detection of the residues of the insecticide imidacloprid in agricultural and environmental samples.
A competitive enzyme-linked immunosorbent assay (ELISA) for the chloronicotinyl insecticide imidacloprid was developed using a polyclonal antibody produced against a hapten conjugated through the imidazolidine to keyhole limpet hemocyanin. In the standard curve of imidacloprid, an IC(50) of 17.3 ng/mL was obtained using a competitive heterologous system at pH 10. Very low cross-reactivity was found for some structurally related compounds including the insecticide thiacloprid. The high cross-reactivity with a metabolite containing the carbonyl group in the imidazolidine moiety suggests the involvement of its polarity and stereochemical fitness in forming the antibody--antigen complex. The effects of various assay conditions, including organic solvents, detergent content, salt concentration, and pH on the sensitivity were evaluated. High-performance liquid chromatography was run for comparison to validate the ELISA with fortified water samples, the correlation being 0.997-0.998 (n = 15) with a slope of 1.10--1.38. The ELISA turned out to be a convenient tool for monitoring imidacloprid residues in agricultural and environmental samples.
Lee
J K
JK
Department of Agricultural Chemistry, Chungbuk National University, Cheongju 361-763, Korea. jlee@cbucc.chungbuk.ac.kr
Ahn
K C
KC
Park
O S
OS
Kang
S Y
SY
Hammock
B D
BD
D002851:Chromatography, High Pressure Liquid; D003429:Cross Reactions; D004784:Environmental Monitoring; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D007093:Imidazoles / Q000032:analysis*; D007306:Insecticides / Q000032:analysis*; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010573:Pesticide Residues / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010573:Pesticide Residues; C082359:imidacloprid