HPLC-MS/MS Determination of Natamycin in Grape Wine

Sample of grape wine (5.00 mL) was diluted with a mixture of acetonitrile-0.1% (φ) formic acid (5+95) to 50 mL in a brown glass volumetric flask, and a portion of the solution was centrifuged for 5 min to have the small grained impurities settled. The supernatant was used for LC separation. Eclipse plus C18 column was used as stationary phase and mixtures of acetonitrile and 0.1% (φ) formic acid in various ratios were used as mobile phase in gradient elution. In MS/MS analysis, ESI+ scanning and MRM were adopted. In preparation of standard curves, blank wine sample of same variety with the objective sample used as the matrix solution to dilute standard solution of natamycin, in order to match the matrix effect. Linear relationship between values of peak area and mass concentration of natamycin was obtained in the range of 0.20-100 μg·L-1, and values of detection limits (3S/N) found for red, white and rose wine were 0.099, 0.024, 0.046 μg·L-1 respectively. Tests for recovery were made by standard addition method at 3 concentration levels, giving results in the range of 87.0%-102%, with RSDs (n=5) ranged from 4.0% to 7.7%.