UHPLC-MS/MS Determination of Metronidazole in Honey

UHPLC-MS/MS was applied to the determination of metronidazole in honey. The sample of honey was dissolved with di-potassium hydrogen phosphate solution, and then extracted with ethyl acetate. The extract was purified with MCS solid phase extraction column. Hypersil Gold-C₁₈ chromatographic column was used as stationary phase, and the mixture of 0.1% (φ) formic acid solution and acetonitrile mixed in different ratio was used as mobile phase in gradient elution. ESI⁺ and multi-reactions monitor were adopted in MS/MS. D4-metronidazole was used as internal standard. Linearity range of metronidazole was found between 0.5 μg·L^-1 and 64.0 μg·L^-1 with lower limit of determination (10S/N) of 0.15 μg·kg^-1. On the base of blank sample, test for recovery was made by standard addition method; values of recovery found were in the range of 95.6%-98.8%, with RSD's (n=6) in the range of 4.2%-8.3%.