Immunoaffinity Column Clean-Up and Liquid Chromatography with Post-Column Derivatization for Analysis of Aflatoxins in Traditional Chinese Medicine

An easy, rapid, and sensitive reversed-phase high-performance liquid chromatographic (HPLC) method with fluorescence detection is proposed for simultaneous determination of aflatoxins B1, B2, G1, and G2 in traditional Chinese medicines. Aflatoxins B1 and G1 were determined as their iodine derivatives, prepared by on-line post-column derivatization. Optimum conditions for formation of the derivatives were investigated. The aflatoxins were separated on a C18 column with acetonitrile–methanol–water, 1:1:4 (v/v), as mobile phase at a flow rate of 1.0 mL min−1. Stability of solutions, and linearity, accuracy, precision, and detection limits were examined to validate the method. Samples were extracted with MeOH–H2O, 70:30 (v/v), followed by clean-up of the extracts with immunoaffinity columns. Overall average recoveries from three different traditional Chinese medicines spiked at levels of 2.57, 5.10, and 6.37 µg kg−1 total aflatoxins ranged from 84.49–103.77%. The method was tested on Rhizoma Corydalis, Fujian Massa Medicata Fermentata, Semen Armenicae Amarum, Herba Ephedrae, Semen Platycladi, etc.