HPLC-MS/MS Determination of Aflatoxins and Their Homologues in Supplementary Cookies for Infants and Young Children

The crushed sample of supplementary cookies for infants and young children was extracted with mixture of acetonitrile, water and acetic acid with volume ratio of 89∶10∶1, and purified by QuEChERS method with purification agents of 50 mg ODS, 30 mg PSA and 30 mg NH₂. HPLC-MS/MS was applied to the determination of 8 aflatoxins and their homologues, i.e. AFB₁, AFB₂, AFG₁, AFG₂, MST, ST, AFM₁ and AFM₂ in the purified liquid. AQ-C₁₈ HP chromatographic column (2.1 mm×100 mm, 3.0 μm) was used as stationary phase, and the mixture of 0.1% (φ) formic acid solution containing 5 mmol·L^-1 ammonium acetate and methanol 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 8 aflatoxins and their homologues were kept in definite ranges, with detection limits (3S/N) in the range of 0.05-0.10 μg·kg^-1 and lower limits of determination (10S/N) in the range of 0.15-0.30 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 76.3%-95.9%, with RSDs (n=6) of determined values in the range of 3.1%-11%.