HPLC Determination of Aflatoxins in Tea in Bags with Extraction by Matrix Solid Phase Dispersion

A method of HPLC for the determination of aflatoxins B1, B2, G1 and G2 in tea in bags with extraction by matrix solid phase dispersion was proposed. The optimized conditions found were as follows: ① mass ratio of sample to dispersant (neutral Al2O3): 1∶4;② volume of the eluant (acetonitrile) used: 6 mL. Symmetry C18 chromatographic column was used as stationary phase, and a mixture of methanol and water (1+1) was used as mobile phase in the separation. Fluorescence detection at the wavelengths of (λex) 365 nm and (λem) 435 nm was adopted in the determination. Linear relationships between values of peak area and mass concentration of aflatoxins B1, B2, G1 and G2 were kept in definite ranges, with detection limits (3S/N) in the range of 0.05-0.15 μg·L-1 and lower limits of determination (10S/N) in the range of 0.15-0.50 μg·L-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 88.3%-96.8%, with RSD′s (n=6) in the range of 4.3%-6.8%.