Determination Of Validamycin Residues In Foodstuffs By Solid-phase Extraction (SPE) And Liquid Chromatography/tandem Mass Spectrometry (LC-MS/MS)

A sensitive and selective analytical method for the determination of validamycin residue in several foodstuffs by solid-phase extraction (SPE) and liquid chromatography/tandem mass spectrometry (LC-MS/MS) was developed. Solvent extraction with methanol-water (9:1, V/V) and cleanup with HLB SPE using water as eluents provided adequate recovery of validamycin. Determination was carried out by LC-MS/MS using 5 mmol/L ammonium acetate buffer (pH 4.5) as mobile phase. The multiple reaction monitoring (MRM) scheme employed involved transitions of the precursor ion to three selected product ions, in which one pair for quantification was m/z 498.3>178.1 and the other two pairs for identification were m/z 498.3>336.3 and 498.3>142.2. The limits of quantification (LOQs) of the method were 0.01 mg/kg depending on the matrix. Intra-and inter-day precisions (relative standard deviations, RSDs) for validamycin were less than 7.1% and 14.8% in 16 types of agro-products, respectively. The repetitive determinations achieved good reproducibility for validamycin residue. The recovery at three concentrations (LOQ,2.5LOQ, and 5LOQ) ranged from 79.3-118.3% in cabbage, potato, onion, carrot, apple, orange, banana, lichee, tea and Skiitake mushroom. The proposed procedure was applied to the analysis of 129 real samples from Xiamen, Fujian province (China). The method should be applicable for validamycin analysis of monitoring validamycin residue in foodstuffs.