Abstract:

An analytical method was established for the determination of propargite, tebuconazole and bromopropylate in Taiwan green jujubes (Zizyphus mauritiana Lam) by gas chromatography-tandem mass spectrometry (GC-MS/MS). The sample was extracted with acetonitrile from the Taiwan green jujubes after treated with a homogenizer. The organic phase was then separated from water phase by adding NaCl. The extract was further purified on a carbon/NH₂ cartridge with elution solvents of acetonitrile/toluene (3:1, v/v). Finally, the target analytes were separated by a capillary gas chromatographic column SLB-5MS (30 m×0.25 mm×0.25 μm). A tandem quadrupole mass spectrometer operated in either full scan mode or in MS/MS mode for multiple reaction monitoring (MRM) was used for the qualitative and quantitative analysis of the constituents, respectively. The results showed that the average recoveries of the three pesticides ranged from 75.8% to 103.6% with the RSDs of 1.7%-9.3% at the spiking levels from 0.01 mg/kg to 0.50 mg/kg (n=5). The calibration curves showed good linearity in the range of 0.01-0.50 mg/kg, with the determination coefficients over 0.99 (R²>0.99). The limits of quantification (LOQs) were 0.01 mg/kg for propargite, tebuconazole and bromopropylate in Taiwan green jujubes. The method is available for the determination of propargite, tebuconazole and bromopropylate pesticide residues in Taiwan green jujubes.

Key words: bromopropylate, gas chromatography-tandem mass spectrometry (GC-MS/MS), propargite, Taiwan green jujubes, tebuconazole