Research


Latest SCI publications

Latest Projects

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 - 2018-02-28

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

The aim of this project is to develop a technique for sampling the biologically available (bioavailable) fraction of sulfur (S), strontium (Sr) and lead (Pb) from soils. Subsequently, the isotopic composition of these elements will analyzed. The motivation behind is that a site-specific variation of isotopic composition of S, Sr and Pb in soil can act as specific fingerprint. This fingerprint is mirrored in plants growing on this soil. The isotopic difference can be caused by variations in the geology, by natural processes (e.g. microbial activities) or by anthropogenic activities (e.g. by combustion of fossil fuels containing S or petrol containing Pb). Diffusive gradients in thin films (DGT) represent an efficient passive sampling technique. DGT takes up elements from soil in the same way plants do, simply by diffusion. In this (bioavailable) fraction, the isotopic composition of the investigated elements will be analyzed by a dedicated mass spectrometer. Within this project, we want to develop a novel technique, which • enables to take up S, Sr and Pb from soil without causing any change in the isotopic composition of these elements. • takes up the part of S, Sr and Pb, which would be taken up by plants (bioavailable fraction) and the isotopic composition of these elements taken up by DGT from soil equals to that of plants grown on the same soil. • allows for the establishment of a direct link of the chemical information stored in soils to the information found in primary agricultural products and therefore allows for provenancing. For the first time, the bioavailable chemical isotopic information is assessed directly. Within this project, new binding layers for S and Sr will be developed making use of the expertise of the collaborating company, which provides an expertise on novel resin materials. The results of this findings will be compared to greenhouse and field experiments. The goal of this approach is that we will be able to determine the site-specific isotopic signal and use it to investigate the origin of agricultural products by comparing their isotopic composition with the bioavailable fraction found in soil.

Supervised Theses and Dissertations