The mass spectrometry laboratory (UR MolSys) at the University of Liège has just acquired a new very high-resolution mass spectrometer based on extremely accurate detection of the frequency of ions’ cyclotronic movement in an intense magnetic field. This equipment is unique in Belgium. This acquisition coincides with the development of an international network of laboratories and manufacturers dedicated to instruments of this type (H2020 programme). Both sides want to get better value from these tools which are capable of measuring masses with relative precision of less than one millionth, while also ushering in new research opportunities in various sectors.
Mass spectrometry is the Swiss army knife of molecular analysis. Its contribution is growing exponentially in basic molecular sciences, physical chemistry, biophysics, theoretical chemistry, biology or even biomedical sciences. It has allowed the emergence of new disciplines known as “omics” such as proteomics, metabolomics, etc. Spectrometry is essential in a large number of applications in analytic chemistry, bioanalysis, environmental sciences, forensic analysis and food safety.
Why such a success? Combined with the analysis of their reactivity during fragmentation, the measurement of the mass of molecules and their complexes allows for their identification, study of their properties and development of accurate assay methods. The sample quantities required are miniscule (picomoles), even raw samples can be analysed. Recently, two dimensions of additional information have been added to technical analysis: the location of the molecules in the sample using imaging and the analysis of the shape using ionic mobility.
MALDI-TOF mass spectrometry imaging of crossed fingerprints - optical image of fingerprints
Different superimposed fingerprints covered with α-Cyano-4-hydroxycinnamic acid matrix (HCCA).
The mass spectrometry laboratory at the University of Liège (MolSys Research Unit, Faculty of Sciences) has very high-performance instruments. Among them, a new arrival: a special spectrometer - unique in Belgium - working with a strong magnetic field, able to distinguish between very similar masses (e.g. between 1000,0000 and 1000,0001) and measure their value with relative precision of less than one millionth. It also allows acquisitions in imaging mode and will soon be used alongside ionic mobility.
This new instrument sees the involvement of twelve academic laboratories and manufacturers of scientific instruments, with each having a preferred area of use, to offer a network which forms part of the European infrastructure of the Horizon 2020 programme. The proposal has been approved and will soon be financed. In collaboration with scientists from all around the world, this network will be used to explore the new scientific fields offered by this spectrometer.
Imaging and ionic mobility at ULiège
In addition to housing the instrument, the University of Liège will focus on mass spectrometry and ionic mobility. Imaging can be used to locate, on a histological section of a biopsy for example, molecules from tissues specific to a pathology or the biodistribution of a drug (molecular microscopy). It can also be used to visualise chemical communication between organisms. There are many potential applications. Ionic mobility is another method used to differentiate molecules (or molecular complexes) based on their shape. Two molecules with the same mass can have different shapes. These two molecules cannot be distinguished using conventional mass spectrometry. They can be separated and characterised using ionic mobility.
Images of a Dario Neri (Zebrafish) larva cut
A: Hematoxylin & eosin from a serial cut
B: Localization of ions specific to a particular tissue
C: automatic determination of the regions corresponding to the organs: blue: brain, red: heart, green: intestine
Together, these techniques are a remarkable multi-faceted tool which must be developed and made available to the scientific community. Exchanges between researchers and the possibility of working on network instruments offers a unique opportunity to access many exceptional instruments. The University of Liège is committed to welcoming researchers for a total of 40 days per year.
More details
Spectrometry refers to various spectral analysis methods used to discover the composition and structure of matter (organic, nitrogenous, solid, liquid, gaseous). Mass spectrometry is used to measure the mass of a chemical or biological substance and to identify said substance. Its principal is based on the gas phase separation of charged molecules (ions) based on their mass/charge ratio.
Therefore, a mass spectrometer comprises the following elements:
- an ionisation source: the molecules are vaporised and ionised using various methods (including matrix-assisted laser desorption/ionisation (MALDI)).
- an analyser: categorises the ions based on their mass using various physical methods.
- a detector: the ions are transformed into electrical signals which can be recorded and analysed.
Contact
Pr Edwin DE PAUW
Laboratoire de spectrométrie de masse
UR MolSys - Faculté des Sciences et plateforme protéomique GIGA
