Research Fellows Directory
Dr Alfredo Quinto-Hernandez
University of Oxford
Biological mass spectrometry is widely used to study biomolecular structure and function. However, the details of the molecular fragmentation processes that lead to the observed ions have not been well studied. Velocity-map imaging (VMI) combines time-of-flight (ToF) mass spectrometry with a measurement of the velocity distribution of each observed fragment ion, yielding a wealth of information on the detailed dynamics of the molecular fragmentation process. Using universal ionization and VMI methods together with the Pixel Imaging Mass Spectrometry (PImMS) multimass imaging sensor, our current research is focused on a number of model peptide compounds in a ‘bottom-up’ approach to understanding the complex molecular non-statistical fragmentation processes exhibited by larger peptides. Through identifying the fragments formed, their relative abundances, the partitioning of energy amongst the various translational and internal degrees of freedom of the products, and the product angular distributions, we expect to explore the evolution of the species under study from parent molecule to fragment ions.
A brand new exploratory project, based on the related technique of spatial-map imaging (SMI), will be developed to map spatial distributions of molecules emitted from the surface of plant cells. There is currently significant interest in determining both the spatial distribution of various molecular species within cells and larger plant structures and the way in which these distributions change in response to external stresses such as drought, disease, or pest infestation. Different types of molecule may be detected preferentially via the use of matrix-assisted laser-desorption ionization with appropriate matrices, but a considerable amount of work will be required in order to optimize both the sample preparation techniques and the experimental parameters in order to achieve optimum spatial and mass resolution.
Interests and expertise (Subject groups)