HPLC determination of aflatoxin residues in traditional Chinese medicine Yinpian with post column photochemical derivation and fluorescence detection

Objective:To investigate the recoveries of aflatoxin(AF) residues analysis of traditional Chinese medicine(TCM) Yinpian using immunoaffinity column HPLC method with post column photochemical derivatization and fluorescence detection,and evaluate the feasibility of the method.To evaluate the contamination status of 120 batches of TCM Yinpian and summarize the rule of contamination.Methods:Samples were prepared through organic solvent extraction and cleaned up with immunoaffinity column sequentially;the recoveries of aflatoxins were then determined by adding aflatoxins standard mixture at the level of 4 μg·kg-1 according to aflatoxin B1 content.Finally,aflatoxins B1,B2,G1 and G2 residue amount in TCM Yinpian was determined.Results:The limit of detection of aflatoxins B1,B2,G1,G2 was 0.44,0.12,0.41,0.16 pg,respectively.Aflatoxins B1,B2,G1,G2 showed good linear relationships at the ranges of 1.74-218.0 pg,0.50-62.17 pg,1.63-203.1 pg and 0.62-61.94 pg,respectively,r﹥0.9999.The recoveries of total aflatoxins and aflatoxin B1 in 87% detected samples were between 60%-120%.9.2% of TCM Yinpian was detected to be contaminated by aflatoxins,and aflatoxins amount in 6.7% exceeded the limit of Chinese Pharmacopoeia of the People's Republic of China 2010.Conclusion:The method showed convenient operation,stable derivation reaction,high sensitivity,good repeatability and little pollution,which meets the requirement of aflatoxin residues determination in most TCM Yinpian.The seeds are easy to be contaminated,so the aflatoxins control in those TCM should be expanded.