UHPLC-MS/MS Determination of 4 Nitrofuran Metabolites in Animal Derived Food

By comparing the advantages and disadvantages of determination methods of the nitrofuran metabolites between GB/T 20752-2006, GB/T 21311-2007 and ministry of agriculture announcement No. 783-1-2006, the key influencing factors of nitrofuran metabolites determination were determined. Hydrochloric acid solution and 2-nitrobenzaldehyde solution were added to the sample of animal derived food without washing of methanol solution, and then the sample solution was derived in water bath at 37 ℃ for 4 h. pH of the sample solution was adjusted to 7.4. After centrifugation, the supernatant was taken, and then passed through HLB solid phase extraction column. The eluate was collected. UHPLC-MS/MS was applied to the determination of 4 nitrofuran metabolites in the sample solution. Waters BEH C₁₈ chromatographic column was used as stationary phase, and the mixture of 0.05% (volume fraction) formic acid solution containing 2.0 mmol·L^-1 ammonium acetate and 2.0 mmol·L^-1 ammonium acetate methanol solution mixed in different ratios was used as mobile phase in gradient elution. ESI⁺ and multiple reaction monitoring mode were adopted in MS/MS. Internal standard method was used for quantitative. Linearity ranges of the 4 nitrofuran metabolites were found in the same range of 0.50-20.0 μg·L^-1 with detection limits (3S/N) in the range of 0.05-0.25 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 94.0%-107%, with RSDs (n=6) of determined values in the range of 1.9%-3.4%. The proposed method was applied to the analysis of proficiency testing samples (19-N866, 19-P653), giving results in consistency with the known values.