Poster (Scientific congresses and symposiums)
Investigation of data independent acquisition for small molecules structure elucidation in image by FT-ICR MS
La Rocca, Raphaël; Mc Cann, Andréa; Far, Johann et al.
2019EU-_FT-ICR_MS advanced school
 

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Abstract :
[en] Mass Spectrometry Imaging (MSI) is an analytical method allowing the mapping of molecules from thin sections of samples after their ionization/desorption usually obtained by MALDI. However, in the case of biological samples, the study of localized metabolic pathways is hampered by the lack of structural identification of the detected molecules even with high mass resolution. In this context, we are developing an independent data acquisition method for MSI by fragmenting all the precursors without prior m/z selection. The obtained MS/MS spectra are then attempted to be deconvoluted with the aim of attributing the fragments to their parents by the help of their spatial distributions.The chosen model for acquiring MSI data is the chemical communication observed between bacteria and fungi colonies, grown on agar- based medium. On this sample, 2 images have been acquired using MALDI-FT-ICR (SolariX XR, 9.4T, fitted with the ParaCell®). The first one, called precursors’ image (PI), is obtained at low collision energy and contains parent ions. The second one, called fragments’ image (FI), has been acquired at greater collision energy, and thus contains mostly their fragment ions. The fragmentation is made in the hexapole. A deconvoluted MS/MS spectrum for each ion in PI is calculated with the help of non-negative least square regression. In a few words, the algorithm tries to recreate the spatial distribution of an ion from FI by a weighted sum of the ions in PI. A deconvoluted MS/MS spectrum of an ion in PI corresponds thus to its weights for each associated ion in FI. A first stage of quality control for evaluating the deconvolution process is made by comparing the reconstructed MS/MS spectrum of a reference ion, to its experimentally acquired MS/MS spectrum. In the present study, the reference molecule is a lipopeptide called viscosin added as reference spots before the image acquisition.The reconstructed MS/MS spectrum for all the peaks in PI are compared to the experimental MS/MS spectrum of viscosin based on two parameters: cosine similarity and the proportion of intensity in the reconstructed spectrum belonging to a true fragment. The obtained results shows a good correlation between the experimentally acquired MS/MS and the reconstructed MS/MS of viscosin, however the algorithm is not yet able to distinguish variables with corresponding spatial distributions. In the future, new algorithms will be developed and tested to overcome the issue of correlated variables to implement the recording of data independent MS/MS images.
Research center :
MolSys - Molecular Systems - ULiège
Disciplines :
Chemistry
Author, co-author :
La Rocca, Raphaël  ;  Université de Liège - ULiège > Département de chimie (sciences) > Laboratoire de spectrométrie de masse (L.S.M.)
Mc Cann, Andréa ;  Université de Liège - ULiège > Département de chimie (sciences) > Laboratoire de spectrométrie de masse (L.S.M.)
Far, Johann  ;  Université de Liège - ULiège > Département de chimie (sciences) > Chimie analytique inorganique
Eppe, Gauthier  ;  Université de Liège - ULiège > Département de chimie (sciences) > Chimie analytique inorganique
De Pauw, Edwin  ;  Université de Liège - ULiège > Département de chimie (sciences) > Chimie analytique inorganique
Quinton, Loïc  ;  Université de Liège - ULiège > Département de chimie (sciences) > Chimie biologique
Language :
English
Title :
Investigation of data independent acquisition for small molecules structure elucidation in image by FT-ICR MS
Publication date :
14 April 2019
Number of pages :
A0
Event name :
EU-_FT-ICR_MS advanced school
Event organizer :
EU_FT-ICR_MS network
Event date :
From 14-04-2019 to 18-04-2019
Audience :
International
European Projects :
H2020 - 731077 - EU_FT-ICR_MS - European Network of Fourier-Transform Ion-Cyclotron-Resonance Mass Spectrometry Centers
Name of the research project :
Eurlipids
Funders :
CE - Commission Européenne [BE]
Available on ORBi :
since 30 May 2019

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