[Simultaneous determination of insecticide in tea samples using QuEChERS-based clean up and ultra-fast liquid...

To develop a method for determination of imidacloprid, acetamiprid, chlorobenzamide and indoxacarb in tea samples using Qu ECh ERS-based pretreatment method and ultra-fast liquid chromatography-tandem mass spectrometry( UFLC-MS/MS).

Tea samples were firstly extracted by acetonitrile-water solution( 4∶ 1, V/V) by vortex and ultrasound, and then 1 g Na Cl and 4 g Mg SO4 were added into the mixture, following by vortex and centrifugation at 8500 r/min for 5 min. Finally the supernatant was purified by Mg SO4 and PSA power, and then the chromatographic separation process was performed on a Waters ACQUITY UPLC BEH C18 column( 2. 1 mm × 100 mm, 1. 7 μm) with a linear gradient elution procedure ofacetonitrile and 0. 1%( V/V) formic acid-5 mmol/L ammonium acetate in water as elution solvent. The multiple reaction monitoring( MRM) in positive mode was used for quantification by internal standard method.

The four insecticides including imidacloprid, acetamiprid, chlorobenzamide, and indoxacarb showed good linearity in the range of 0. 20-50. 0 μg/L with coefficients( r) higher than 0. 9998. The limits of detection( LODs) varied from 0. 1 μg/kg to 0. 3 μg/kg. The recoveries of spiked tea samples in the range of 88. 4%-98. 8% at the three concentrations of 1. 0 μg/kg, 40. 0μg/kg and 80. 0 μg/kg, while the relative standard deviations( RSD) were all less than10%.

The proposed method is simple, fast, sensitive and accuracy, and can be used for qualitative and quantitative analysis of imidacloprid, acetamiprid, chlorobenzamide, andindoxacarb in tea samples.