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

Abstract

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.