Simultaneous analysis ofAlternariatoxins and citrinin in tomato: an optimised method using liquid chromatography-tandem mass spectrometry

Abstract

Alternaria toxins and citrinin are mycotoxins produced by fungi growing on different raw materials and agricultural commodities. Maximum levels of these toxins in foods are currently under consideration by the European Commission as a risk management measure. In this study, a new quantitative method is described for the determination of five Alternaria toxins and citrinin in tomato and tomato juice samples based on LC-MS/MS detection. Samples were extracted with pure methanol, followed by a derivatisation step with 2,4-dinitrophenylhydrazine to improve the determination of tenuazonic acid and to decrease the wide polarity difference between the compounds of interest. Samples were purified on hydrophilic-modified styrene polymer solid-phase extraction cartridges. High-performance liquid chromatographic columns packed with different core–shell materials were tested for the separation of toxins and a C-18 phase was in the final method applied to achieve sufficient separation of all relevant analytes. A key element of this approach was to prove successful transferability of the method to three different triple quadrupole mass spectrometers. A full single laboratory method validation was performed on two LC-MS/MS systems and performance characteristics met the predefined requirements. Moreover, the method was used in an international proficiency test and the satisfactory z-scores obtained (−0.1 to 0.8 in tomato juice samples) demonstrated the reliability of the approach described. The method will be validated in an inter-laboratory collaborative study and if the criteria for method precision are met, the method will be proposed as a new Work Item to the European Committee for Standardisation.

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

“…The selected reversed phase column was described before to be favorable for the separation of the five Alternaria toxins, namely AOH, AME, ALT, TeA, and TEN [27]. By optimization of eluents, temperature, and the multi-step gradient, we were able to separate our 17 target analytes of highly diverse polarity.…”

Spotlight on the Underdogs—An Analysis of Underrepresented Alternaria Mycotoxins Formed Depending on Varying Substrate, Time and Temperature Conditions

“…A few HPLC-MS/MS multi-methods have been published for the simultaneous quantification of the main ATs TeA, AOH, AME, ALT, TEN [33] and underrepresented ones such as ATX-I in tomato products [34], additionally ATX-II, STTX-III, ATL, isoALT, AA-III and AAL toxins TB1 and TB2 in fruit juices, vegetable juices and wine [13], in bakery products, sunflower seeds and vegetable oils [35], further including conjugated toxins of AOH and AME in cereal products [36] and also stable isotope dilution assay for several ATs in various commercial food samples [37]. …”

A fully automated and fast method using direct sample injection combined with fused-core column on-line SPE–HPLC for determination of ochratoxin A and citrinin in lager beers

“…The pK a values of OTA are in the ranges 4.2-4.4 and 7.0-7.3, respectively, for the carboxyl group of the phenylalanine moiety and the phenolic hydroxyl group of the isocoumarin part [39]. CIT is weak organic acid with a pK a value of 3.55 and log P of 0.81 [40]. The extracted mycotoxins should be in their neutral form to be well retained by hydrophobic interactions.…”