HPLC-MS/MS Determination of Residual Amount of Dodine in Fruits

HPLC-MS/MS was applied to the determination of residual amount of dodine in fruits. The sample was extracted with methanol by shaking for 3-5 min. After centrifugation, the supernatant obtained was evaporated to dryness. The residue was dissolved with the mobile phase and used for HPLC-MS/MS determination, in which BEH C18 column (2.1 mm×100 mm, 1.7 μm) was used as chromatographic column, and mixture of acetonitrile and 5 mmol·L-1 ammonium acetate (80+20) was used as mobile phase; positive electrospray ionization as well as multiple reaction monitoring mode was used in the MS detection. Ion pair used for qualitative analysis was: m/z 185.9,56.7, and ion use for quantitative analysis was m/z 56.7. Linear relationship between values of peak area and mass concentration of dodine was obtained in the range of 5.0-500.0 μg·L-1, with lower limit of determination (10S/N) of 0.04 mg·kg-1. Tests for recovery and precision were made by addition of standard solution of dodine at 3 concentration levels to fruit samples which were then analyzed by the proposed method. Values of recovery and RSD′s (n=10) obtained were in the ranges of 80.0% to 104.6% and 4.3% to 14% respectively.