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Sujet de stage / Master 2 Internship

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LC-HRMS/MS and NMR analysis of C-13 labeled mouse urine. Structural elucidation of unknown metabolites

Contact: HUBER Gaspard, , gaspard.huber@cea.fr, +33 1 69 08 64 82
High resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR) are two complementary techniques for the analysis of complex mixtures in solution such as the metabolome. During this trainee-ship, the opportunity to analyze, by these two techniques, urine samples labeled with C-13, in addition to other unlabeled samples obtained under similar conditions, should allow great progress in the structural elucidation of unknown compounds.
Possibility of continuation in PhD: Oui
Deadline for application:31/01/2021

Full description:
Context and M2 research project

Metabolomics aims to characterize all the "small molecules" (<1500 Da) of a biological sample and is based mainly on two analytical techniques: high resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR). [1,2] Despite the high complementarity of these two approaches, they are still very rarely used together for the annotation of the metabolome. While LC-HRMS analysis of a single complex biological sample can detect thousands of signals at concentrations down to nanomolar, NMR allows structural identification of the most abundant metabolites in that sample. However, this last technique suffers from a lack of sensitivity. Thus, the access to "biological material" fully labeled with C-13 (stable isotope of C-12) is an opportunity allowing: (1) to increase spectral resolution and thus increase the number of metabolites that can be characterized by NMR, and (2) facilitate the assignment of elementary compositions of HRMS signals from unknown metabolites by comparison of LC-HRMS profiles of labeled and unlabeled samples collected in the same conditions.
The M2 research project aims to analyze, by very high resolution mass spectrometry (Orbitrap Fusion, Thermo) coupled with liquid chromatography and by heteronuclear 2D NMR, the urine of mice labeled with carbon-13 and to compare them with unlabeled urine. This study will aim to synergistically exploit the data obtained via both analytical techniques to identify some unknown metabolites detected in the samples. The structural elucidation of the compounds will also be supported by LC-HRMS / MS acquisitions.

Working environment

The M2 traineeship will take place in two CEA Saclay laboratories: (1) the drug metabolism study laboratory (LEMM), Joliot institute; and (2) the laboratoire structure et dynamique par résonance magnétique (LSDRM), IRAMIS.
LEMM is specialized in the analysis of the metabolome since 2002, thus accumulating expertise in the development and validation of LC-MS methods for profiling biofluids, and tissue and cell extracts. It is equipped with an analytical platform consisting of 6 low resolution instruments (QqQ) and 7 high and very high resolution instruments (Orbitrap and Q-TOF).
LSDRM is an expert in developing novel approaches for magnetic resonance spectroscopy. It is equipped with 6 NMR spectrometers from 1.0 to 11.7 T.

Profile of the candidate and application

Engineering student and/or M2 in chemistry. Specialty in analytical chemistry or organic chemistry with an interest in analytical chemistry and more particularly mass spectrometry and NMR. Desired start date: February 2021.
Applications (CV and cover letter) should be sent to annelaure.damont@cea.fr and gaspard.huber@cea.fr

[1] Theodoridis G A et al. Liquid chromatography–mass spectrometry based global metabolite profiling: A review. Analytica Chimica Acta 2012, 711, 7-16.
[2] Nagana Gowda G A et al. Recent Advances in NMR-Based Metabolomics. Anal. Chem., 2017, 89 (1), 490-510.
Technics/methods used during the internship:
mass spectrometry, nuclear magnetic resonance

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