Simultaneous determination of aflatoxin B_1,B_2,G_1,G_2,M_1,M_2 in Eupolyphaga Steleophaga by immunoaffinity column clean-up and HPLC-FLD with post-column photochemical derivatization

Abstract

The contamination of aflatoxin B_1,B_2,G_1,G_2,M_1 and M_2 in Eupolyphaga Steleophaga was determined by immunoaffinity column clean-up and HPLC-FLD with post-column photochemical derivatization. Chromatographic separations were carried out using a Cloversil C_(18) column( 4. 6 mm×250 mm,5 μm) that were eluted in isocratic with methanol-acetonitrile-water( 20 ∶ 20 ∶ 60) as the mobile phase. The excitation wavelength and the emission wavelength of fluorescence detector were maintained at 360 nm and 450 nm,respectively. The flow rate was 0. 8 m L·min~(-1),and the column temperature was 30 ℃ ． The sample was prepared using the immunoaffinity column,then the recovery was measured with 75. 47%-101. 8% with RSD values lower than 6. 7%. A total of 20 batches of Eupolyphaga Steleophaga samples were assayed. According to the Chinese Pharmacopoeia( 2015 edition,part 1),the aflatoxin B_1 limit should be less than 5 μg·kg~(-1),and the sum of aflatoxins( AFB_1,AFB2,AFG_1,AFG_2) should be less than 10 μg·kg-1. Therefore,the positive rate of the 20 samples was 50. 0%,and 7 batches of samples exceeded the standard,and the over-standard rate was as high as 70. 0%. Among them,aflatoxins B_1,B_2,G_1,G_2,M_1,and M_2 were detected in three batches( SD-1,AH-1,AH-3),and aflatoxins B_1,B2,G1,G2,and M1 were detected in one batch( AH-7). The results showed that the newly developed method in this work is suitable for the simultaneous determination of six aflatoxins in Eupolyphaga Steleophaga,and also suggested that it should be of high values to take the contamination with aflatoxins into concerns.