Objective:To establish the liquid chromatography-mass spectrometry (LC-MS) method for rapid determination of aflatoxin B1 (AFB1) and aflatoxin G1 (AFG1) in traditional Chinese animal medicines (TCAM)

and evaluate the contamination of two aflatoxins in the sample of 6 frequently-used TCAM. Method:The sample was extracted with 84% acetonitrile; then the extract was evaporated and the residue was re-suspended in methanol. The separation was carried out on a high performance liquid chromatograph equipped with a C18 column (2.1 mm×100 mm

3 μm)

with methanol-4.0 mmol·L ammonium acetate-0.1% formic acid as the mobile phase for gradient elution. The quantification was carried out with a tandem quadrupole mass spectrometer by using selective reaction monitoring (SRM) in positive ion mode. Result:The matrix effect for AFB1 and AFG1 in 6 TCAMs was acceptable

ranging from 82% to 119%. Recovery tests were performed with Hirudo as the representative matrix at three different concentration levels (low

middle

and high). The absolute recoveries and the extraction recoveries of AFB1 and AFG1 were between 80% and 117%. Precision RSD was between 1.8%-7.5% and repeatability RSD was between 5.1%-14%. The developed method was applied to evaluate the contamination of two aflatoxins in 55 samples of 6 TCAMs

and 4 of these 55 samples were contaminated

of which Eupolyphaga Steleophage samples showed a contamination rate of 33.3% with a contamination level of 1.26-26.3 μg·kg-1. Conclusion:TCAMs like Eupolyphaga Steleophage are susceptible to aflatoxin contamination and attentions should thus be paid to their potential hazards. It is necessary to take appropriate measures to reduce the risk of aflatoxin contamination in various sections during the production of medicinal materials.