Development of competitive enzyme-linked immunosorbent assays (ELISAs) based on monoclonal antibodies for chloronicotinoid insecticides imidacloprid and acetamiprid

Enzyme-linked immunosorbent assays (ELISAs) based on monoclonal antibodies (MoAbs) for chloronicotinoid insecticides imidacloprid and acetamiprid were developed. The MoAbs for either imidacloprid or acetamiprid were obtained utilizing mice with 3-[5-(2nitroiminoimidazolidin-1-ylmethyl)-2-pyridylthio]propionic acid or 3-[5-(N-(1cyanoiminoethyl)-N-methylaminomethyl)-2-pyridylthio] propionic acid haptens conjugated to bovine serum albumin, respectively. Both MoAbs (33C3-1-1 for imidacloprid and 45E10-11 for acetamiprid) characterized by an indirect competitive ELISA showed high sensitivity and low cross-reaction to related compounds. Direct competitive ELISAs (DC-ELISAs) with 33C3-1-1 for imidacloprid or with 45E10-1-1 for acetamiprid were tested on spiked vegetable and fruit samples without clean-up procedures. The mean recovery of the either assay measured by DC-ELISA ranged from 80 to 120% for imidacloprid or from 80 to 100% for acetamiprid, respectively. Both recovery tests for imidacloprid and acetamiprid showed good performance by DC-ELISA at the permitted level (0.5ppm for imidacloprid and 1ppm for acetamiprid) in vegetable and fruit. The result demonstrates that these assays could be easier to handle and as well as lesser expensive than usual high-performance assays such as gas chromatography (GC), high performance liquid chromatography (HPLC) and GC-mass spectrometry (GC-MS).