HPLC-MS/MS Determination of 5 Alternaria Toxins in Fruits with QuEChERS

After homogenate, the fruit sample was extracted ultrasonically for 30min with acetonitrile (containing 1% formic acid). After centrifugation, the supernatant was taken and then N-propyl ethylenediamin and C₁₈ were added for purification. After centrifugation, the mixture was filtered with 0.22 μm filter membrane. HPLC-MS/MS was applied to the determination of 5 Alternaria toxins in the filtrate. Hypersil GOLD chromatographic column was used as stationary phase, and the mixture of acetonitrile and 0.1% (φ, the same below) formic acid solution mixed in different ratios was used as mobile phase in gradient elution. ESI and multi-reactions monitor mode were adopted in MS/MS. Linear relationships between values of peak area and mass concentration of the 5 Alternaria toxins were kept in definite ranges, with lower limits (10S/N) of determination in the range of 0.02-1.0 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 93.3%-111%, with RSDs (n=6) of determined values in the range of 3.0%-9.7%.