Rapid screening of 44 pesticide residues in ginger and scallion by ultra performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry

Abstract

An analytical method was established for the simultaneous determination of 44 pesticide residues in ginger and scallion by ultra performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry (UPLC-Q-TOF/MS). The samples were extracted with acetonitrile containing 0.1% (v/v) acetic acid aqueous solution, and cleaned-up by primary secondary amine (PSA) and octadecyl bonded silica (C18) adsorbents. The compounds were separated on a Poroshell 120 SB-C18 column (100 mm×3.0 mm, 2.7 μm) with 0.1% (v/v) formic acid aqueous solution containing 5 mmol/L ammonium acetate-acetonitrile as mobile phases under gradient elution. The eluent was determined by UPLC-Q-TOF/MS with electrospray ionization in positive mode. The quantification analysis was performed with the external standard method. In all ions MS/MS mode, the compounds were qualitatively screened and confirmed by one data acquisition. The correlation coefficients (r) were greater than 0.995 in the linear ranges of the 44 pesticides. The limits of quantification (LOQs, S/N=10) of the 44 pesticides were 2.5-5.0 μg/kg. At the three spiked levels, the recoveries were between 73.4% and 113.7% with the relative standard deviations (RSDs) ranging from 0.7% to 12.1% (n=6). The method effectively improves the determination efficiency of pesticide residues screening by high-resolution mass spectrometry.