[Determination of selected mycotoxins in food. I. Selection of optimal conditions for the determination of aflatoxin M1 in milk using high-performance liquid chromatography methods].

The aim of this study was to perform a optimized method for determination of aflatoxin M1 in milk. The manner of extraction and clean-up of milk extracts as well conditions of reaction of aflatoxin M1 with TFA and HPLC was described. The main steps of optimized method were: extraction of samples with chloroform, clean-up of extracts on SPE C18 columns and by means of extraction with n-hexane, derivatisation of aflatoxin M1 with TFA (60 degrees C, 6 minutes) to acetal form--aflatoxin M2a and determination of aflatoxin by means of the RP-HPLC technique. The mobile phase was a mixture of methanol, isopropanol and water (18 + 7 + 75). Fluorometric detection was made at 370/418-700 nm. The mean recovery of aflatoxin M1 dependent on fortification level was 62-67%, limit of detection was 0.01 microgram/1 of milk.