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Research project (§ 26 & § 27)
Duration : 2017-10-01 - 2020-09-30

Eels are an endangered species of which the migration behaviour is only little understood. In this research project, analysis of eel otoliths and eel soft tissues by means of (LA)-ICP-SFMS and (LA)-MC ICP-MS for elemental (Li, Ba, Mg, B, Fe, Zn, Sr, Ca, Mn, Zr, Pb, U, S) and 87Sr/86Sr isotope analysis. Eel of different provenance will be provided. A special focus is set on glass-eel, representing the juvenile status of the fish. Since the samples are extremely challenging, existing analytical protocols will be further developed and optimized for the respective research question. The to be developed database will be compared with water data in order to reconstruct migration and provenance of the investigated fish samples.
Research project (§ 26 & § 27)
Duration : 2017-07-01 - 2019-05-31

Metabolomics (and 13C based metabolic flux) data generated by GC/MS is complimentary to LC/MS data and exhibits characteristics that require additional consideration when mapping changes in pathways. Nevertheless, targeting intermediates of the important pentose-phosphate pathway, gas chromatographic separation and mass spectrometric detection of the involved isomers remains the gold standard. In addition together with fit-for-purpose derivatization methods, GC/MS provides unrevealed coverage of metabolites over a wide polarity range. The typical 70 eV EI spectral data generated by GC/MS includes significant fragmentation of the analyte, which complicates the ability to trace incorporation of stable isotope labels of the intact molecule. While there are academic software packages available for this purpose, they are not adapted for commercial users. Further, traditional 70 eV EI spectra is generated on nominal mass resolution mass spectrometers, reducing selectivity and analytical confidence, particularly for assessment of structural information of fragments of derivatized metabolites. Agilent's forthcoming GC/Q-TOF platform includes a low-energy EI source, which allows for the relative preservation of analyte ions (i.e., metabolite molecular ions), which has the potential to greatly simplify stable isotope tracing through the metabolic pathway compared to traditional GC/MS techniques. Further, the high mass resolution and accurate mass measurement performance of the GC/Q-TOF significantly increases selectivity in complex biological matrices and improves identity confirmation of fragment ions for increased metabolite identification capabilities and confidence. An additional benefit of the low energy source in connection with collision induced dissociation functionality is the possiblity of assessing positional information of the 13C atoms incorporated into the metabolites of interest allowing elucidation of critical branching points in metabolic networks. In this project, we propose to investigate the use of Agilent's forthcoming GC/Q-TOF platform in MFA, with an emphasis on low-energy ionization for preservation of molecular ions in aiding isotope tracing. Further, this work will serve as a proof-of-concept and early stage development in extending the existing VistaFlux software to support GC/Q-TOF data in providing a comprehensive LC/MS and GC/MS qualitative fluxomics solution.

Supervised Theses and Dissertations