ION MOBILITY-MASS SPECTROMETRY TO EXTEND ANALYTICAL PERFORMANCE IN THE DETERMINATION OF ERGOT ALKALOIDS IN CEREAL SAMPLES L. Carbonell-Rozas , M. Hernández-Mesa , L. Righetti , F. Monteau , F.J. Lara , L. Gámiz-Gracia , B. Le Bizec , C. Dall’Asta , A.M. García-Campaña , G. Dervilly 1,2
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Department of Analytical Chemistry, University of Granada, Campus Fuentenueva, 18071 Granada, Spain. Oniris, INRAE, LABERCA, 44300 Nantes, France. Department of Food and Drug, University of Parma, Parco Area delle Scienze, 43124 Parma, Italy 1
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rozas@ugr.es This work evaluates the potential of travelling wave ion mobility spectrometry (TWIMS) to improve the analytical performance, in terms of selectivity and concentration sensitivity, of liquid chromatography-mass spectrometry (LC-MS) workflows applied to the determination of ergot alkaloids (EAs). EAs are mycotoxins produced mainly by fungi of the Claviceps genus, prevalent in cereals whose ingestion can cause ergotism in humans and animals. The simultaneous determination of EAs with current LC-MS methods has some limitations since several of these compounds are epimers and show similar retention times and an identical mass-to-charge ratio (m/z). In this regard, taking advantage of the third dimension offered by TWIMS, which provides the measurement of the rotationally averaged collision cross section (CSS), we report the first CCS database for the main EAs to support their unequivocal identification. The generated CCS database was inter-laboratory cross-validated and compared with CCS values predicted by machine-learning models. In this context, slight differences were observed in the experimental CCS values obtained for ergotamine, ergosine and ergocristine and their corresponding epimers (ΔCCS/CCS between 3.3 and 4 %), which were sufficient to achieve peak-to-peak resolution in the TWIMS dimension. In addition, a LCTWIM-MS method was applied to the analysis of the main EAs in cereal samples. The integration of TWIMS in the LC-MS workflow improved the signal-to-noise ratio (S/N) between 2.5 and 4-fold; therefore, signal sensitivity was improved. Furthermore, cleaner mass spectra were observed as EAs were also separated from the chemical background in the TWIMS dimension. The analysis of cereal samples resulted in the finding of positive samples in EAs with concentration levels between 8.3 and 36.8 μg kg-1 in barley samples, and between 5.2 and 65.0 μg kg-1 in wheat samples. Acknowledgements: Research Project RTI2018-097043-B-I00 financed by MCIN/AEI /10.13039/501100011033/ FEDER “Una manera de hacer Europa” and Junta de Andalucía-Programa Operativo FEDER (B-AGR-202-UGR20). Keywords: travelling wave ion mobility-mass spectrometry, ergot alkaloids, cereal samples, collision cross section.
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