Determination of Alternaria toxins in tomato, wheat and sunflower seeds by SPE and LC-MS/MS - a method validation through a collaborative trial.

BACKGROUND Alternaria toxins are ubiquitous contaminants in highly consumed food products. Therefore, they are candidates to be regulated by EU legislation. In this context the availability of reliable analytical methods is a keystone both for protecting the health of the citizens and the smooth functioning of the European market. OBJECTIVE This paper describes an advanced LC-MS/MS method based on isotope dilution quantification suitable for the determination of altenuene, alternariol, alternariol monomethyl ether, tenuazonic acid and tentoxin in tomato puree, wheat and sunflower seeds. METHOD The method has been validated in a collaborative trial that included the analysis of both, spiked and naturally contaminated food commodities. Twenty-three participants contributed with analytical data. RESULTS The average recoveries and relative standard deviations for repeatability and reproducibility obtained across the tested matrices were: 97%, 8.0% and 23%, for altenuene, respectively; 95%, 9.2% and 17% for alternariol, respectively; 98%, 6.4% and 13% for alternariol monomethyl ether, respectively; 97%, 4.2% and 9.3% for tenuazonic acid, respectively; and 102%, 5.6% and 15% for tentoxin, respectively. The method enabled the determination of all tested Alternaria toxins close to or below 1 µg/kg. CONCLUSION Overall, the method showed a satisfactory trueness and precision, complying with the requirements for the monitoring of mycotoxins in food in the EU. It is currently under evaluation by the European Committee for Standardization for the adoption as a standard method.