Abstract: A multiresidue analytical method was developed for the determination of 215 pesticides in ginger using liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The pesticide residues were extracted from ginger by acetonitrile containing 1% (v/v) acetic acid, cleaned-up by a Sep-Pak Vac cartridge, eluted with acetonitrile-toluene (3:1, v/v). The eluate was concentrated to about 0.5 mL with a rotary evaporator, dried with nitrogen at room temperature. The sample was redissolved in an acetonitrile-water mixture (3:2, v/v), then analyzed using LC-MS/MS in multiple reaction monitoring (MRM) mode via positive electrospray ionization. The recovery test was conducted at spiked level of limit of quantification (LOQ). The validation results were as follows: the overall recoveries were from 68.1% to 132.6% of which 94.4% of the recoveries were from 70% to 120%, with the relative standard deviations of 0.4%-25.0%. The limits of detection (S/N=3) and the limits of quantification (S/N=10) were 0.01-70.45 μg/L and 0.04-234.84 μg/L, respectively. The results demonstrated that this method is simple and with acceptable sensitivity and accuracy to meet the requirements of the multiple pesticide residue analysis. This method is applicable to determine 215 pesticide residues in ginger.

Key words: ginger , multiple pesticide residues, liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS)