Multiresidue determination of nicotinoid insecticide residues in drinking water by liquid chromatography with electrospray ionization mass spectrometry

A multianalyte method has been developed for the confirmation and quantification of four neonicotinoids, acetamiprid, imidacloprid, thiacloprid and thiamethoxam in drinking water. These insecticides were extracted from water by solid-phase extraction (SPE) LiChrolut EN. Analytes' determination and quantification were performed by liquid chromatography-mass spectrometry (LC-MS). Extraction efficiency experiments demonstrated the ability of this method to extract nicotinoids from water samples. Confirmatory analysis was carried out by LC-electrospray ionization-mass spectrometry (LC-ESI-MS) instrumentation equipped with a single-quadrupole mass filter. MS data acquisition was performed by two-ion selected ion monitoring (SIM) program. Average recoveries of the four analytes from drinking water samples were in the range of 95 and 104% with relative standard deviations (R.S.D.) < 20%. The limit of quantification (LOQ) for each of the four insecticides was 0.03 μg L−1.