Estimation of Imazethapyr in Agricultural Water by Its Cross-Reactivity with either Imazaquin or Imazapyr ELISA Kits

The cross-reactivity expressed by commercially available ELISA kits developed for two imidazolinone herbicides can be used for estimating the concentration of another compound within the chemical class in surface water and groundwater collected from agricultural fields. Imazaquin and imazapyr kits are used for estimating imazethapyr. Results on authentic samples indicate that dissolved constituents in the matrix can produce false positives with the imazaquin kit. Spiked HPLC water showed a pH dependence of the dose−response curve for imazethapyr when using the imazaquin kit. Practical concentration ranges for estimating imazethapyr are 1−125 μg/L with the imazapyr kit and 8−800 μg/L for the imazaquin kit. Keywords: Imazethapyr; imazaquin; imazapyr; residue estimation; ELISA; agricultural water