Publications of Jean-François Focant
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See detailUse of Blood Volatiles as Trace Evidence
Dubois, Lena ULiege; Perrault, Katelynn ULiege; Stefanuto, Pierre-Hugues ULiege et al

Poster (2019, February 20)

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See detailGCxGC coupled to TOFMS: A powerful tool for complex applications in Separation Science
Focant, Jean-François ULiege

Scientific conference (2019, February)

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See detailMultimodal chemometric approach for the analysis of human exhaled breath in lung cancer patients by TD-GC ×GC-TOFMS
Pesesse, Romain ULiege; Stefanuto, Pierre-Hugues ULiege; SCHLEICH, FLorence ULiege et al

in Journal of Chromatography. B, Biomedical Applications (2019)

Lung cancer is the deadliest cancer in developed countries. To reduce its mortality rate, it is important to enhance our capability to detect it at earlier stages by developing early diagnostic methods ... [more ▼]

Lung cancer is the deadliest cancer in developed countries. To reduce its mortality rate, it is important to enhance our capability to detect it at earlier stages by developing early diagnostic methods. In that context, the analysis of exhaled breath is an interesting approach because of the simplicity of the medical act and its non-invasiveness. Thermal desorption comprehensive two-dimensional gas chromatography time of flight mass spectrometry (TD-GC×GCTOFMS) has been used to characterize and compare the volatile content of human breath of lung cancer patients and healthy volunteers. On the sampling side, the contaminations induced by the bags membrane and further environmental migration of VOCs during and after the sampling have also been investigated. Over a realistic period of 6 h, the concentration of contaminants inside the bag can increase from 2 to 3 folds based on simulated breath samples. On the data processing side, Fisher ratio (FR) and random forest (RF) approaches were applied and compared in regards to their ability to reduce the data dimensionality and to extract the significant information. Both approaches allow to efficiently smooth the background signal and extract significant features (27 for FR and 17 for RF). Principal component analysis (PCA) was used to evaluate the clustering capacity of the different models. For both approaches, a separation along PC-1 was obtained with a variance score around 35%. The combined model provides a partial separation with a PC-1 score of 52%. This proof-of-concept study further confirms the potential of breath analysis for cancer detection but also underlines the importance of quality control over the full analytical procedure, including the processing of the data. [less ▲]

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See detailCompositional elucidation of heavy petroleum base oil by GC×GC-EI/PI/CI/FI-TOFMS
Giri, Anupam; Coutriade, Marion; Racaud, Amandine et al

in Journal of Mass Spectrometry (2019)

Comprehensive two‐dimensional gas chromatography (GC×GC) coupled to time‐of‐flight mass spectrometry is a powerful separation tool for complex petroleum product analysis. However, the most commonly used ... [more ▼]

Comprehensive two‐dimensional gas chromatography (GC×GC) coupled to time‐of‐flight mass spectrometry is a powerful separation tool for complex petroleum product analysis. However, the most commonly used electron ionization (EI) technique often makes the identification of the majority of hydrocarbons impossible due to the exhaustive fragmentation and lack of molecular ion preservation, prompting the need of soft‐ionization energies. In this study, three different soft‐ionization techniques including photo ionization (PI), chemical ionization (CI), and field ionization (FI) were compared against EI to elucidate their relative capabilities to reveal different base oil hydrocarbon classes. Compared to EI (70 eV), PI (10.8 eV) retained significant molecular ion (M+‧) information for a large number of isomeric species including branched‐alkanes and saturated mono‐cyclic hydrocarbons along with unique fragmentation patterns. However, for bi‐/poly cyclic naphthenic and aromatic compounds, EI played upper hand by retaining molecular as well as fragment ions to identify the species, whereas PI exhibited mainly molecular ion signals. On the other hand, CI revealed selectivity towards different base oil groups, particularly for steranes, sulfur‐containing thiophenes, and esters; yielding protonated molecular ions (M+H) + for unsaturated and hydride abstracted ions (M‐H+) for saturated hydrocarbons. FI, as expected, generated intact molecular ions (M+‧) irrespective to the base oil chemical classes. It allowed elemental composition by TOFMS with a mass resolving power up to 8,000 (FWHM) and a mass accuracy of 1 mDa, leading to the calculation of heteroatomic content, double bond equivalency, and carbon number of the compounds. The qualitative and quantitative results presented herein offer a unique perspective into the detailed comparison of different ionization techniques corresponding to several hydrocarbon classes. [less ▲]

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See detailGC×GC-(HR)TOFMS in colorectal cancer metabolomics
Di Giovanni, Nicolas ULiege; Cojocariu, Cristian; Silcock, Paul et al

Conference (2018, December 18)

Colorectal cancer globally affects more than one million new persons each year, and kills more than 700.000. Nevertheless, its diagnosis is still largely based on invasive tissue sampling and gaps remain ... [more ▼]

Colorectal cancer globally affects more than one million new persons each year, and kills more than 700.000. Nevertheless, its diagnosis is still largely based on invasive tissue sampling and gaps remain in the understanding of its pathogenesis, with complex combinations between lifestyle, genetics, epigenetics, chronic inflammation (IBD) and microbiota. Untargeted metabolomics is one of the approaches that can be used to solve these issues. To do so, an optimized and validated (NIST SRM 1950) comprehensive GC×GC-(HR)TOFMS method we developed was used, that also included an in-house QC system and data processing based on multiple statistical techniques. Practically, we analyzed serum samples from patients affected by colorectal cancer (CRC, n = 18) and by colorectal cancer in remission (R-CRC, n = 17), and samples from healthy patients matched for biases (HC, n = 19 and R-HC, n = 17). We highlighted candidate biomarkers able to discriminate between matched HC and CRC or R-CRC, which discrimination potential was assessed using supervised and unsupervised models, discriminant analysis and ROC curves. Overfitting was avoided by re-sampling and test validation testing. Annotation used full mass spectrum, linear retention indices and accuracte mass provided by state-of-the-art high-resolution (HR) time-of-flight mass spectrometry. Finally, we studied the main metabolic pathways altered in the disease, whether in active or in remission state. In addition, newly developed GC-MS Orbitrap was applied, using the same global method, to biological replicates to determine the capacity of this technology to perform in untargeted metabolomics as well as to validate the results previously obtained. [less ▲]

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See detailFingerprinting glues using HS-SPME GC×GC-HRTOFMS: a new powerful method allows tracking glues back in time
Cnuts, Dries ULiege; Perrault, Katelynn ULiege; Stefanuto, Pierre-Hugues ULiege et al

in Archaeometry (2018), 60(6), 1361-1376

The use of glues for stone tool hafting is an important innovation in human evolution. Compared to other organic remains, glues are preserved more frequently, though mainly in small spots. Reliable ... [more ▼]

The use of glues for stone tool hafting is an important innovation in human evolution. Compared to other organic remains, glues are preserved more frequently, though mainly in small spots. Reliable identification requires chemical molecular characterization, which is traditionally performed by gas chromatography-mass spectrometry (GC-MS). Current methods of extraction and derivatization prior to GC-MS are destructive and require relatively large samples, which is problematic for prehistoric glue residues. In this paper, we discuss the results of an experimental study using a new method (HS-SPME-GC×GC-HRTOFMS) that proves effective for identifying small quantities of compound glues. The method is non-destructive with an improved sensitivity in comparison to traditional GC-MS, and it has a high potential for prehistoric samples. [less ▲]

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See detailGCxGC-HRTOFMS Analysis of Base Oils with Chemical Ionization, Field Ionization and Photoionization
Dane, J; Giri, A; Okuda, K et al

Poster (2018, December)

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See detailBreath Print for Asthma Phenotyping
Zanella, Delphine ULiege; Stefanuto, Pierre-Hugues ULiege; SCHLEICH, FLorence ULiege et al

Scientific conference (2018, November 08)

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See detailImportance of sorbent material selection for VOCs sampling: application on bacterial cultures and breath
Franchina, Flavio ULiege; Zanella, Delphine ULiege; Stefanuto, Pierre-Hugues ULiege et al

Scientific conference (2018, November 08)

Bacterial volatile organic compounds (VOCs) have been considered as sensitive and specific biomarkers for bacterial phenotyping in both human biofluids (breath, blood, urine, etc.) and culture media. The ... [more ▼]

Bacterial volatile organic compounds (VOCs) have been considered as sensitive and specific biomarkers for bacterial phenotyping in both human biofluids (breath, blood, urine, etc.) and culture media. The possibility of using VOCs markers for bacterial identification would open a new frontier for developing more efficient diagnostic techniques of infections. Besides the biological differences in in vivo/in vitro environments, the importance of using the same sampling technique and sorbent phase is crucial for the translation and validation of biomarker discovery. In the present contribution, GC×GC-MS was exploited to compare and evaluate different adsorption materials for thermal desorption tubes for VOCs sampling. Specifically, the following parameters were evaluated: sensitivity, selectivity, reproducibility and linear range. Five different adsorbent materials (Carbopack Y, X, B, Carboxen 1000 and Tenax), packed singularly or in combination, were tested on a standard mixture (15 compounds). The tubes packed with Tenax showed the best reproducibility (max 14% RSD) and sensitivity, with ~24 average fold increase compared to Carbopack Y+X+Carboxen 1000, which was second in terms of sensitivity. The two better performing thermal desorption tubes, Tenax and Carbopack Y+X+Carboxen 1000, was also evaluated on E. coli, S. aureus, and P. aeruginosa cultures. Both tubes were able to discriminate between the 3 culture types, but improved sensitivity and reproducibility were obtained with Tenax tubes. A similar comparison on tube performances was carried out on breath samples. [less ▲]

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See detailCharacterization of hafting adhesives using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry
Perrault, Katelynn ULiege; Dubois, Lena ULiege; Cnuts, Dries ULiege et al

in Separation Science Plus (2018), 1-12

The determination of the presence and the composition of residues from organic materials on archeological objects allows the behavior of our prehistoric ancestors to be better understood. The functional ... [more ▼]

The determination of the presence and the composition of residues from organic materials on archeological objects allows the behavior of our prehistoric ancestors to be better understood. The functional analysis of tools used for daily life activities, such as hunting or hide working, represents an important source of information. However, the chemical characterization of residues from archeological artifacts represents an analytical challenge. On one hand, the residues are made of different natural materials containing hundreds of chemicals. This complexity requires advanced analytical procedures to separate and identify the constituents. On the other hand, the low quantity and the advanced degradation require sensitive and non-destructive methods. In this study, an approach employing headspace sampling (solid-phase microextraction) with comprehensive two-dimensional gas chromatography coupled to highresolution-time-of-flight mass spectrometry was developed for the characterization of adhesive residues on simulated archeological artifacts. First, the performance of the analytical system was evaluated on a standard mixture and a pine resin sample. Next, adhesives and adhesives mixtures were analyzed that represented typical compositions that have been witnessed in archaeological applications. This analytical approach is a gateway into new potential for headspace organic residue characterization as a first step of analysis prior to altering residues for additional characterization. [less ▲]

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See detailCOMPLETE STATISTICAL WORKFLOW FOR OPTIMIZED USED OF GC×GC-TOFMS
Stefanuto, Pierre-Hugues ULiege; Focant, Jean-François ULiege

Poster (2018, October)

In the last years, multidimensional chromatography methods have undergone numerous developments on the technical side. Several commercial systems of two dimensional gas chromatography coupled to high ... [more ▼]

In the last years, multidimensional chromatography methods have undergone numerous developments on the technical side. Several commercial systems of two dimensional gas chromatography coupled to high-resolution mass spectrometer (GC×GC-HRTOFMS) are now commercially available. However, the users are still facing challenges for method optimization and data processing steps. This research aims to develop a complete optimization and processing workflows for GC×GC-TOFMS application. The simplification of the technique would be a game change for broader transfer of this technology to the industry. [less ▲]

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See detailEnvironmental Forensics of POPs
. Over a Few Exemples
Focant, Jean-François ULiege

Scientific conference (2018, June 01)

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See detailGC×GC-(HR)TOFMS Over a Few Recent Applications
Focant, Jean-François ULiege

Scientific conference (2018, June)

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See detailGC×GC-(HR)-TOFMS for Metabolomics and Volatilomics
Focant, Jean-François ULiege; Zanella, Delphine ULiege; Di Giovanni, Nicolas ULiege et al

Conference (2018, June)

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