IUPAC

Coordination of collaborative trial studies for the determination of aflatoxins in various food matrices by combination of a clean-up step using immunoaffinity columns (IAC) coupled with thin layer chromatography (TLC). The project is addressed to needs of developing countries and the method validation will be carried out by involving only laboratories from those countries.

The determination of aflatoxins on the matrices under examination is usually performed by IAC- HPLC, the IAC clean-up being capable to a suitable purification for the determination of aflatoxins at ppb levels. Many food commodities are commonly produced in geographical regions where analytical laboratoies rely mostly on robust and simple-to-use analytical instrumentation. Those producer countries are usually not equipped with HPLC, while they need to evaluate contamination at levels approaching the legal limits enforced in many industrialized countries such as the European Community. TLC is a viable alternative to HPLC. Therefore, the project will take into consideration the determination of aflatoxins by IAC and TLC in peanuts, pistachios, paprika, figs, and corn. By using this approach a simple, reliable, not expensive method (repeated use of IAC is aimed)will be available for developing countries. In addition, the TLC methods currently available will be modified by not using chlorinated solvents.

The project, which was carried out between 2000 and 2003, aimed to obtain a robust and simple validated method capable of quantifying aflatoxin B1 in corn and peanuts at levels of 1-10 ng/g using thin-layer chromatography (TLC). The project did not achieve its objective, but it did provide some valuable lessons that the authors felt were important to share with the IUPAC community. An article describing the background and results of the collaborative study, as well as lessons learned and conclusions has been published in Chem. Int. July-Aug 2004, p.7-9.