Tracking emerging mycotoxins in food: development of an LC-MS/MS method for free and modified Alternaria toxins.

Puntscher, Hannes; Kütt, Mary-Liis; Marko, Doris; Warth, Benedikt; Skrinjar, Philipp; Mikula, Hannes; Fröhlich, Johannes; Podlech, Joachim

Mycotoxins produced by Alternaria fungi are ubiquitous food contaminants, but analytical methods for generating comprehensive exposure data are rare. We describe the development of an LC-MS/MS method covering 17 toxins for investigating the natural occurrence of free and modified Alternaria toxins in tomato sauce, sunflower seed oil, and wheat flour. Target analytes included alternariol (AOH), AOH-3-glucoside, AOH-9-glucoside, AOH-3-sulfate, alternariol monomethyl ether (AME), AME-3-glucoside, AME-3-sulfate, altenuene, isoaltenuene, tenuazonic acid (TeA), tentoxin (TEN), altertoxin I and II, alterperylenol, stemphyltoxin III, altenusin, and altenuic acid III. Extensive optimization resulted in a time- and cost-effective sample preparation protocol and a chromatographic baseline separation of included isomers. Overall, adequate limits of detection (0.03-9 ng/g) and quantitation (0.6-18 ng/g), intermediate precision (9-44%), and relative recovery values (75-100%) were achieved. However, stemphyltoxin III, AOH-3-sulfate, AME-3-sulfate, altenusin, and altenuic acid III showed recoveries in wheat flour below 70%, while their performance was stable and reproducible. Our pilot study with samples from the Austrian retail market demonstrated that tomato sauces (n = 12) contained AOH, AME, TeA, and TEN in concentrations up to 20, 4, 322, and 0.6 ng/g, while sunflower seed oil (n = 7) and wheat flour samples (n = 9) were contaminated at comparatively lower levels. Interestingly and of relevance for risk assessment, AOH-9-glucoside, discovered for the first time in naturally contaminated food items, and AME-3-sulfate were found in concentrations similar to their parent toxins. In conclusion, the established multi-analyte method proved to be fit for purpose for generating comprehensive Alternaria toxin occurrence data in different food matrices.ᅟ<graphic></graphic>

MYCOTOXINS; LIQUID chromatography-mass spectrometry; GLUCOSIDES; TENTOXIN; ALTERNARIOL; ALTERNARIA

Analytical & Bioanalytical Chemistry, 2018, Vol 410, Issue 18, p4481

1618-2642

Academic Journal

10.1007/s00216-018-1105-8