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

Abstract

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. Graphical abstractᅟ Electronic supplementary materialThe online version of this article (10.1007/s00216-018-1105-8) contains supplementary material, which is available to authorized users.

The Alternaria Mycotoxin Alternariol Triggers the Immune Response of IL‐1β‐stimulated, Differentiated Caco‐2 Cells

“…The used standard of alternariol from Alternaria species (AOH) had a purity of ≈96 % and was purchased from Sigma-Aldrich (St. Louis, MO). To check for impurities with structural analogy LC-MS measurements according to Puntscher et al [19] were conducted and revealed the presence of 2.1-3.4% of alternariol monomethyl ether (AME). Stock solutions of AOH and dexamethasone (Dex, HPLC ≥ 98%; Sigma-Aldrich) were prepared in DMSO (Carl Roth GmbH&Co., Karlsruhe, Germany).…”

Functional impairment triggered by altertoxin II (ATXII) in intestinal cells in vitro: cross-talk between cytotoxicity and mechanotransduction

“…ATXII is well known to be formed by Alternaria alternata strains in vitro, i.e., in rice-based culture (Schwarz et al 2012; Zwickel et al 2016a). However, data concerning its occurrence in food and feed are limited and great effort is continuously devoted to the development/optimization of analytical methods for its detection (Puntscher et al 2018; Zwickel et al 2016b). To add complexity to this scenario, actual data indicate that ATXII may promptly react with food constituents (Aichinger et al 2018).…”

European analytical column number 47

“…One of DAC-EuChemS objectives is to support its delegates on the organization of local events open to the international community through dissemination of the event within the Professional Network. In 2019 we have scheduled the 2nd Cross-Border Seminar on Electroanalytical Chemistry (CBSEC), 10…”

“…These heavy metals ions are also identified and detected using electrochemical methods in environment [7] where analytics in water plays a fundamental role regarding contaminants and upcoming antibiotics [8]. Interesting is also the measurement of mycotoxins [9] and their tracking in food using LC-MS/MS [10]. The microplastic pollution of water is an increasing issue worldwide, therefore a review on the challenges for analytical chemistry regarding the analysis of microplastics in the environment has a high citation rate [11].…”