Analysis of total aflatoxins in food by HPLC and UHPLC

Aflatoxins are one of the mycotoxins which are produced from the microorganisms such as Aspergillus flavus, Aspergillus parasiticus and Aspergillus nomius living in tropical or subtropical regions and, they have a strong carcinogenic action. It has been reported that the higher level of aflatoxins than the regulated level in Food Sanitation Act has been detected mainly from imported grain, pulse and spice. Recently, it is also reported that the aflatoxins have been detected even from the Japanese domestic foods.

The Japanese Government has announced on the 31st of March, 2011 that the regulation in Food Sanitation Act related to the aflatoxins will be strengthened and, the new act will become mandatory from the 1st of October, 2011. In the previous regulation, the quantity of aflatoxin B1 giving the strongest carcinogenic effect in the natural compounds available, must be regulated to be lower than 10 g/kg. However, in the present regulation, it is strengthened so that the total aflatoxins (sum of aflatoxin B1, B2, G1 and G2) must be lower than 10 ug/kg. In the new procedure of the present regulation, the derivatization method by using of trifluoroacetic acid (TFA) in combination with HPLC including fluorescence detector has been recommended in order to improve the sensitivity of aflatoxin B1 and G1. In addition to the derivatization method, the utilization of multi-functional columns or immunoaffinity colums has been recommended to improve the reproducibility and recovery in the sample preparation procedure.

In this application note, the procedure has been applied to both conventional HPLC and UHPLC.