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Ahmed Ben Faleh

Cette personne a quitté l’EPFL

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Publications associées (22)

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A gas phase approach for glycan analysis: Combining ultrahigh-resolution ion mobility spectrometry with cryogenic vibrational spectroscopy

Ahmed Ben Faleh

The last decades have been punctuated by the development of revolutionary analytical technologies that have enabled the analysis of biomolecular structures and unraveled the roles they play in biological systems. However, certain classes of biomolecules re ...

EPFL2021

Combining Liquid Chromatography and Cryogenic IR Spectroscopy in Real Time for the Analysis of Oligosaccharides

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Ali H Abikhodr

While the combination of liquid chromatography (LC) and mass spectrometry (MS) serves as a robust approach for oligosaccharide analysis, it has difficulty distinguishing the smallest differences between isomers. The integration of infrared (IR) spectroscop ...

Amer Chemical Soc2024

Identification of Mobility-Resolved N-Glycan Isomers

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Priyanka Bansal, Robert Paul Pellegrinelli

Glycan analysis has evolved considerably during the last decade. The advent of high-resolution ion-mobility spectrometry has enabled the separation of isomers with only the slightest of structural differences. However, the ability to separate such species ...

AMER CHEMICAL SOC2022

Using Hadamard Transform Multiplexed IR Spectroscopy Together with a Segmented Ion Trap for the Identification of Mobility-Selected Isomers

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Vasyl Yatsyna, Ali H Abikhodr

The high isomeric complexity of glycans makes them particularly difficult to analyze. While ultra-high-resolution ion mobility spectrometry(IMS) can offer rapid baseline separation of many glycan isomers,their unambiguous identification remains a challengi ...

2023

Using SLIM-Based IMS-IMS Together with Cryogenic Infrared Spectroscopy for Glycan Analysis

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Priyanka Bansal, Ali H Abikhodr, Vasyl Yatsyna, Natalia Yalovenko

The isomeric heterogeneity of glycans poses a great challenge for their analysis. While combining ion mobility spectrometry (IMS) with tandem mass spectrometry is a powerful means for identifying and characterizing glycans, it has difficulty distinguishing ...

2020

Separation and Identification of Glycan Anomers Using Ultrahigh-Resolution Ion Mobility Spectrometry and Cryogenic Ion Spectroscopy

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Valeriu Scutelnic

The analysis of carbohydrates, or glycans, is challenging for established structure-sensitive gas-phase methods. The multitude of possible stereo-, regio- and structural isomers make them substantially more complex to ana-lyze than DNA or proteins, and no ...

2019

Identification of human milk oligosaccharide positional isomers by combining IMS-CID-IMS and cryogenic IR spectroscopy

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Vasyl Yatsyna, Ali H Abikhodr

High-resolution ion mobility spectrometry (IMS) coupled with cryogenic infrared spectroscopy has proven to be a powerful technique for the identification of oligosaccharides. However, the need for an extensive database, combined with the scarcity of pure s ...

2023

Combining ultra-high resolution ion-mobility spectrometry with cryogenic IR spectroscopy for the study of biomolecular ions

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Robert Paul Pellegrinelli, Natalia Yalovenko

Double-resonance spectroscopic schemes in combination with cryogenic ion traps are the go-to techniques when isomer-specific high-resolution spectra are required for analysis of molecular ions. Their limitation lies in the requirement for well-resolved, is ...

2019

High-throughput cryogenic spectroscopy for glycan analysis

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Valeriu Scutelnic

A method for analyzing a plurality of molecules with cryogenic vibrational spectroscopy including the steps of providing a packet of molecules in a ionized form, injecting the packet into an ion mobility section, spatially separating the ions of the packet ...

2019

Multistage Ion Mobility Spectrometry Combined with Infrared Spectroscopy for Glycan Analysis

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Priyanka Bansal

The structural complexity of glycans makes their characterization challenging, not only because of the presence of various isomeric forms of the precursor molecule but also because the fragments can themselves be isomeric. We have recently developed an IMS ...

2023

A new approach for identifying positional isomers of glycans cleaved from monoclonal antibodies

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Priyanka Bansal, Vasyl Yatsyna, Natalia Yalovenko

Glycosylation patterns in monoclonal antibodies (mAbs) can vary significantly between different host cell types, and these differences may affect mAbs safety, efficacy, and immunogenicity. Recent studies have demonstrated that glycan isomers with the termi ...

2021

Device, system, and method for ion fragmentation by use of an ion mobility device and messenger tagging

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke

A device for fragmenting ions by collision induced dissociation, the device intended to be used together with a planar ion mobility apparatus, the device including a first conductive grid having a plurality of first openings, the first conductive grid conf ...

2023

Combining Ultrahigh-Resolution Ion-Mobility Spectrometry with Cryogenic Infrared Spectroscopy for the Analysis of Glycan Mixtures

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke

The isomeric complexity of glycans make their analysis by traditional techniques particularly challenging. While the recent combination of ion mobility spectrometry (IMS) with cryogenic IR spectroscopy has demonstrated promise as a new tech-nique for glyca ...

2019

High-Throughput Multiplexed Infrared Spectroscopy of Ion Mobility-Separated Species Using Hadamard Transform

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Ali H Abikhodr, Vasyl Yatsyna

Coupling vibrational ion spectroscopy with highresolution ion mobility separation offers a promising approach for detailed analysis of biomolecules in the gas phase. Improvements in the ion mobility technology have made it possible to separate isomers with ...

AMER CHEMICAL SOC2022

New Approach for the Identification of Isobaric and Isomeric Metabolites

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Ali H Abikhodr

The structural elucidation of metabolite molecules is important in many branches of the life sciences. However, the isomeric and isobaric complexity of metabolites makes their identification extremely challenging, and analytical standards are often require ...

2023

Identification of N-glycan positional isomers by combining IMS and vibrational fingerprinting of structurally determinant CID fragments

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Priyanka Bansal

While glycans are present on the surface of cells in all living organisms and play key roles in most biological processes, their isomeric complexity makes their structural characterization challenging. Of particular importance are positional isomers, for w ...

ROYAL SOC CHEMISTRY2022

How General Is Anomeric Retention during Collision-Induced Dissociation of Glycans?

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Eduardo Carrascosa Casado, Robert Paul Pellegrinelli, Lei Yue

: Despite the essential role that glycans play in many biological processes, their isomeric com-plexity makes their structural determination partic-ularly challenging. Tandem mass spectrometry has played a central role in glycan analysis, and recent work h ...

2020

A method and system to build an ir fingerprint database for the structural identification of biomolecules

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Priyanka Bansal, Robert Paul Pellegrinelli

A method, system, and computer-readable medium for identifying and creating a database of isomers and isobars of molecules including the steps of performing isomer or isobar separation on molecules to obtain separate isomeric or isobaric molecules, measuri ...

2022

A New Strategy Coupling Ion-Mobility-Selective CID and Cryogenic IR Spectroscopy to Identify Glycan Anomers

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Eduardo Carrascosa Casado, Priyanka Bansal, Robert Paul Pellegrinelli, Lei Yue

Determining the primary structure of glycans remains challenging due to their isomeric complexity. While high-resolution ion mobility spectrometry (IMS) has recently allowed distinguishing between many glycan isomers, the arrival-time distributions (ATDs) ...

2022

Identifying Mixtures of Isomeric Human Milk Oligosaccharides by the Decomposition of IR Spectral Fingerprints

Thomas Rizzo, Ahmed Ben Faleh, Stephan Warnke, Vasyl Yatsyna, Ali H Abikhodr

The analysis of glycans presents a significant challenge that arises from their isomeric heterogeneity. While high-resolution ion mobility spectrometry (IMS) has shown the ability to resolve subtly different glycan isomers, their unambiguous assignment rem ...

2021