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 B-1, B-2, G(1), and G(2) in traditional Chinese medicines. Aflatoxins B, and G, 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 C-18 column 1 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 mu g 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.