Photochemical-fluorimetric method for the determination of the insecticide imidacloprid in water samples Original Research Article

A photochemically induced fluorimetric method for the determination of imidacloprid is proposed, based on the conversion of imidacloprid into the fluorophore 1-(6-chloro-3-pyridyl-methyl)-2-(hydroxyimino)-3,4-didehydroimidalozolidene. In aqueous medium, this compound shows native fluorescence with an excitation maximum at 334 nm and an emission maximum at 377 nm. The linear concentration range of application was 2.5–100.0 ng ml−1 of imidacloprid, with a relative standard deviation of 1.6% (for a level of 10 ng ml−1) and a detection limit of 0.7 ng ml−1. The method was applied to check whether imidacloprid was present above this limit in waters from Granada (Spain). It was validated applying the standard addition methodology. Recovery levels of the method reached 100% in all cases.