Quantitation of imidacloprid in liquid and solid formulations by reversed-phase liquid chromatography: collaborative study

A liquid chromatographic (LC) method was developed for quantitation of the synthetic insecticide imidacloprid in liquid and solid formulations. Samples are dissolved or extracted in solvent and analyzed by reversed-phase LC with propiophenone as internal standard. Fourteen laboratories in 7 countries participated in the collaborative study of the method. Each collaborator was provided with reference standard, internal standard, and matched-pair samples of imidacloprid technical, flowable, wettable powder, fertilizer, and granular formulations. Collaborators were instructed to use peak area measurements for quantitation. The reversed-phase LC method for determination of imidacloprid in liquid and solid formulations has been adopted first action by AOAC International