Abstract:

A method was developed for the determination of imidacloprid and acetamiprid residues in tea using gel
permeation chromatography (GPC)-ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).
Tea samples were extracted with acetonitrile under ultrasonic irradiation and cleaned up with GPC. The elution fractions
at retention times between 10 and 17 min were collected for subsequent analysis. The portions collected from GPC were
blown to dryness under nitrogen gas stream and then the residue was re-dissolved with acetonitrile-0.1% formic acid. The
calibration curves developed were linear in the range of 0.5–100 μg/L with a correlation coefficient higher than 0.99. The
limits of detection (LODs) for imidacloprid and acetamiprid were 2.0 and 1.0 μg/kg, and the limits of quantification (LOQs)
were 5.0 and 3.0 μg/kg, respectively. The average recoveries of the method at three different spiked levels ranged from
76.94% to 91.68% for imidacloprid and acetamiprid with relative standard deviations (RSDs) from 2.67% to 7.90%.

Key words: imidacloprid, acetamiprid, gel permeation chromatography (GPC), ultra performance liquid chromatographytandemmass spectrometry (UPLC-MS/MS), tea