Development of multi-mycotoxin UHPLC-MS/MS methods and application to oat and beer samples

  • Lorenzo De Colli

Student thesis: Doctoral ThesisDoctor of Philosophy

Abstract

An analytical UHPLC-MS/MS method was developed and validated for the identification and quantitation of 42 mycotoxins in unprocessed oat grains intended for human consumption. The method included all the mycotoxins listed under the current European legislation as well as a wide range of analytes of emerging toxicological interest. A rapid, mechanically-assisted, QuEChERS-based sample preparation was employed. The simple and straightforward protocol provided a high degree of accuracy and sample throughput, allowing a single laboratory operator to process up to 60-70 samples a day. The methodology was employed to investigate the effect of the fungicide treatment and whether the oat varieties had an impact on mycotoxin type and concentration in a total of 165 oat samples collected over three consecutive years (2015-2017) from two different geographic areas (Teagasc experimental farms) in Ireland. The oats treated with fungicides, regardless the year and the type of variety, generally contained higher mycotoxin levels, with few exceptions. Furthermore, the co-occurrence of multiple mycotoxins, including the emerging and masked mycotoxins, was reported in Irish oats for the first time upon investigation of the natural co-occurrence of 42 mycotoxins in 208 unprocessed oat grains grown in Ireland during 2015-2016 and produced using conventional, organic, or gluten free farming systems. The year of sampling had minor influence on the mycotoxin content of Irish oats, while sowing season and farming system seemed to have a higher impact on the production of certain mycotoxins. The most frequently quantified compounds were HT-2 (51%) and T-2 (41%), with gluten free oats containing significantly lower concentrations of HT-2 compared to conventionally produced oats. Also, a number of rarely or never reported mycotoxins of toxicological interest were detected. Finally, the QuEChERS-based protocol was adapted and evaluated on beer samples, improving analysis time over the very majority of the published methods. The analysis of 27 commercial beers originated from different countries did not show residues of mycotoxins at concentrations above the LOQs of the method.
Date of AwardJul 2021
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SponsorsTeagasc Walsh Scholarship
SupervisorChristopher Elliott (Supervisor) & Martin Danaher (Supervisor)

Keywords

  • Mycotoxins
  • LC-MS/MS
  • food safety
  • method development
  • sample preparation
  • oats
  • beer
  • cereals
  • emerging contaminants
  • natural toxins

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