DETERMINATION OF ENNIATINS AND BEAUVERICIN BY NON-AQUEOUS CAPILLARY ELECTROPHORESIS–TIME OF FLIGHT MASS SPECTROMETRY IN ALL IONS MODE M.M. Delgado-Povedano, Francisco J. Lara, Emilio Borrego-Marín, Laura Gámiz-Gracia, Ana M. García-Campaña Avda. de Fuente Nueva s/n, 18071, Granada (University of Granada, Faculty of Sciences, Department of Analytical Chemistry) Spain mmdelgado@ugr.es Enniatins (ENN) and beauvericin (BEA) are considered emerging mycotoxins that have been traditionally determined by liquid chromatography coupled to tandem mass spectrometry (MS/MS). However, to the best of our knowledge, no analytical methods based on capillary electrophoresis (CE)-MS/MS has been reported so far. Despite the absence of easily ionizable groups, the ionophoric character of these compounds makes them compatible with CE separation. Due to their apolar nature, in this work, a non-aqueous CE (NACE) method coupled to QTOF-MS is proposed for the first time to identify and quantify these mycotoxins. Separation was achieved in 4 min under optimum conditions: 40 mM ammonium acetate in 80:20 (v/v) MeCN-MeOH (buffer), 30 kV (voltage), 80 cm (capillary length), 20 ºC (capillary temperature) and 50 mbar × 20 s (injection). Higher selectivity can be achieved when compared with LC due to the formation of exclusive CE adducts such as [M+CH CH NH ] . The “All ions” acquisition mode was selected as it allows the quantification of the 3
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usual enniatins, for which standards are available, and the identification of unusual enniatins, for which standards are not available. The method was validated for wheat samples, obtaining LOQs between 5 and 10 μg/kg, recovery values >87.3%, and intra- and inter-day precision values (RSDs) <15.2% in all cases. The method was applied to 29 wheat samples, finding 25 positives for ENNB (16.1-1480 μg/kg), 19 for ENNB1 (19.9-550 μg/kg), 7 for ENNA (10-55μg/kg), 4 for ENNA1 (12.677 μg/kg) and 4 for BEA (12.3-16.4 μg/kg) and two other ENNs (tentatively identity confirmed). Acknowledgement: Financial support of the Spanish Ministry of Science, Innovation and Universities (RTI2018-097043-B-I00) and the Junta de Andalucía - Programa Operativo FEDER (BAGR-202-UGR20). M.M.D.P. is grateful for a postdoctoral contract to the Junta de Andalucía (DOC_00230). Keywords: enniatins, NACE–QTOF MS/MS, beauvericin, all-ions, wheat.
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