Development and Application of a Two-Phase Clean-Up System in Food Samples Prior to Fluorescence Analysis of Aflatoxins.

A new method based on the use of a two-phase separation system is proposed for the clean-up of aflatoxins after their extraction from food samples. After extraction from the sample with an appropriate solvent, aflatoxins contained in organic solvent diffuse to the aqueous phase. At that stage their relative concentration is measured fluorimetrically at 350 nm (λexc). Different organic solvents were tested, and the composition of the aqueous phase was varied. The data obtained showed that the best efficiencies were observed with toluene and PBS-65% methanol. The method was simpler and shorter, and capable of monitoring aflatoxins in samples with a LOD equal to 0.3 µg kg−1 (AFB1). However, the proposed method shows limited selectivity and could thus serve as a screening method for total aflatoxins or be combined with chromatographic techniques for individual aflatoxin determination. [ABSTRACT FROM AUTHOR]