References of "Focant, Jean-François"
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See detailInvestigation on human cadaveric VOC by TD-GCxGC-TOFMS
Stefanuto, Pierre-Hugues ULg; Stadler, Sonja; Pesesse, Romain et al

Poster (2013, May)

The study of the ‘smell of death’ is a challenging task. Analytical chemists who try to understand human decomposition are facing very complex mixtures of analytes present at various levels. For the last ... [more ▼]

The study of the ‘smell of death’ is a challenging task. Analytical chemists who try to understand human decomposition are facing very complex mixtures of analytes present at various levels. For the last few decades, investigations have been conducted to better learn the process of body decomposition by mean of the measurement of the Volatile Organic Compounds (VOCs) released during decay1. However, the chemical profile of the decomposition odor is still far from being elucidated. Indeed, the complexity of the VOC mixtures makes this profiling difficult to be carried out by a classical gas chromatography mass spectrometry (GC-MS) approach. In previous studies, we developed direct-sampling based approaches for cadaveric VOC analysis from grave soils and decaying bodies by mean of thermal desorption (TD) coupled to comprehensive two-dimensional GC coupled to time-of-flight MS (GC×GC-TOFMS)2,3,4. They were based on the use of human analogs (Sus domesticus L. carcasses). For the present study, we investigated the VOC profile of early stage decomposition of human bodies. We analyzed samples collected during different trials organized during different seasons in a body farm located in Texas. Samples included environmental controls, pig carcasses, and human bodies (protected or not from scavenger insects). The data processing was performed in the light of identifying possible seasonal and species variations. Both peak capacity enhancement and spectral deconvolution helped to characterize VOC mixtures and improve comparisons of profiles. Acknowledgements: Human samples were collected during the project “Development and validation of standard operating procedures for measuring microbial populations for estimating a post-mortem interval” Grant Award No. 2010-DN-BX-K243. The authors of that grant are acknowledged for giving us the opportunity to access cadavers for sampling. 1. Vass, A.A. et al. Decompositional odor analysis database. J Forensic Sci (2004) 49, 1–10. 2. Brasseur C. et al. Comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry for the forensic study of cadaveric volatile organic compounds released in soil by buried decaying pig carcasses. J Chromatogr A (2012) 1255, 163–170. 3. Dekeirsschieter, J. et al. Enhanced characterization of the smell of death by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GCxGC-TOFMS). PLoS ONE (2012) 7, e39005. 4. Stadler, S. Characterization of volatile organic compounds from human analogue decomposition using thermal desorption coupled to comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry. Anal Chem (2013) 85, 998–1005. [less ▲]

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See detailUser-friendly method for GCxGC optimization
Stefanuto, Pierre-Hugues ULg; Dimandja, Jean-Marie; Focant, Jean-François ULg

Poster (2013, May)

Almost 30 years are gone since the first paper about multidimensional GC was published by John B. Phillips 1. After several years of developing process, Comprehensive Two Dimensional Gas Chromatography ... [more ▼]

Almost 30 years are gone since the first paper about multidimensional GC was published by John B. Phillips 1. After several years of developing process, Comprehensive Two Dimensional Gas Chromatography systems are in the commercialization step of its live time. During this period, the advantages of GC×GC, regarding to classical D1 system, were clearly demonstrated 2. However, the new parameters involve in a GC×GC method are still not completely understand and people don’t use it at the maximum of its capacity. According to the literature more and more group are using GC×GC for different kind of applications. In most of these researches, GC×GC was used for its separation power. Unfortunately, the orthogonality and the column set are most of the time poorly optimized. To help people in this important step, we develop an user-friendly method to choose the best column combination and the best separation parameters for a particular application. All these developments were based on different mix of standard call the Century mix and the Dimandja mix. These are the descendants of the Phillips mix create in 2003 by J. Dimandja 3. These mixtures contain homologous series of compounds representing the polarity and the volatility range commonly sees in GC×GC. This method is based on the Retention Index obtained in a classical GC analysis and projected in the 2D space. Using this projection method, we identified four major types of orthogonality based on the peak dispersion obtained. We name those: Normal, Reverse, Hybrid and Transpose orthogonality. To characterize these observations, we developed the Orthogonality Index. Going back to the mathematical definition of orthogonality, this factor is the angle formed between the alkane line and the aromatic hydrocarbon line in the chromatographic space. Using this predictive tool, people should be able to choose the best column set and to optimize easily the separation parameters. 1. Phillips, J.B., Luu, D., Pawliszyn, J.B. & Carle, G.C. Multiplex gas chromatography by thermal modulation of a fused silica capillary column. Anal. Chem. 57, 2779–2787 (1985). 2. Dimandja, J.-M.D. Comprehensive 2-D GC provides high-performance separations in terms of selectivity, sensitivity, speed, and structure. Anal. Chem. 76, 167A–174A (2004). 3. Dimandja, J., Clouden, G. & Colón, I. Standardized test mixture for the characterization of comprehensive two-dimensional gas chromatography columns: the Phillips mix. J Chromatogr a 1019, 261–272 (2003). [less ▲]

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See detailUser-friendly method for GCxGC optimization
Stefanuto, Pierre-Hugues ULg; Dimandja, Jean-Marie; Focant, Jean-François ULg

Conference (2013, May)

Almost 30 years are gone since the first paper about multidimensional GC was published by John B. Phillips 1. After several years of developing process, Comprehensive Two Dimensional Gas Chromatography ... [more ▼]

Almost 30 years are gone since the first paper about multidimensional GC was published by John B. Phillips 1. After several years of developing process, Comprehensive Two Dimensional Gas Chromatography systems are in the commercialization step of its live time. During this period, the advantages of GC×GC, regarding to classical D1 system, were clearly demonstrated 2. However, the new parameters involve in a GC×GC method are still not completely understand and people don’t use it at the maximum of its capacity. According to the literature more and more group are using GC×GC for different kind of applications. In most of these researches, GC×GC was used for its separation power. Unfortunately, the orthogonality and the column set are most of the time poorly optimized. To help people in this important step, we develop an user-friendly method to choose the best column combination and the best separation parameters for a particular application. All these developments were based on different mix of standard call the Century mix and the Dimandja mix. These are the descendants of the Phillips mix create in 2003 by J. Dimandja 3. These mixtures contain homologous series of compounds representing the polarity and the volatility range commonly sees in GC×GC. This method is based on the Retention Index obtained in a classical GC analysis and projected in the 2D space. Using this projection method, we identified four major types of orthogonality based on the peak dispersion obtained. We name those: Normal, Reverse, Hybrid and Transpose orthogonality. To characterize these observations, we developed the Orthogonality Index. Going back to the mathematical definition of orthogonality, this factor is the angle formed between the alkane line and the aromatic hydrocarbon line in the chromatographic space. Using this predictive tool, people should be able to choose the best column set and to optimize easily the separation parameters. 1. Phillips, J.B., Luu, D., Pawliszyn, J.B. & Carle, G.C. Multiplex gas chromatography by thermal modulation of a fused silica capillary column. Anal. Chem. 57, 2779–2787 (1985). 2. Dimandja, J.-M.D. Comprehensive 2-D GC provides high-performance separations in terms of selectivity, sensitivity, speed, and structure. Anal. Chem. 76, 167A–174A (2004). 3. Dimandja, J., Clouden, G. & Colón, I. Standardized test mixture for the characterization of comprehensive two-dimensional gas chromatography columns: the Phillips mix. J Chromatogr a 1019, 261–272 (2003). [less ▲]

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See detailTime Controlled Cryogenic Zone Compression (t- CZC) GC-HRMS. Increasing sensitivity to the Attogram Level?
Krumwiede, D; Mehlmann, H; Focant, Jean-François ULg et al

Conference (2013, March)

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See detailDu Côté Obscur au Côté Clair de la Force…
Focant, Jean-François ULg

Learning material (2013)

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See detailMaking sense of the fume: GCxGC-TOFMS analysis of mainstream tobacco smoke
Brokl, Michal ULg; Bishop; Wright et al

Conference (2013, January)

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See detailCharacterizing human decomposition odour: an application of TD-GCxGC-TOFMS
Stadler, S; Stefanuto, Pierre-Hugues ULg; Brokl, Michal ULg et al

Conference (2013, January)

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See detailStudy of complex VOC mixtures by GCxGC-TOFMS
Focant, Jean-François ULg

Conference (2013, January)

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See detailFurther exploration in the quest of orthogonality
Stefanuto, Pierre-Hugues ULg; Dimandja, Jean-Marie; Focant, Jean-François ULg

Conference (2013, January)

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See detailForensic Cadaveric Decomposition Profiling by GC×GC-TOFMS Analysis of VOCs
Focant, Jean-François ULg; Stefanuto, Pierre-Hugues ULg; Brasseur, Catherine ULg et al

in Chemical Bulletin of Kazakh National University (2013), 72(4), 177-186

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See detailLevels of Dechloranes and PBDEs in Serum from Central European Population
Brasseur, Catherine ULg; Focant, Jean-François ULg

in Organohalogen Compounds (2013), 75

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See detailCharacterization of Volatile Organic Compounds from Human Analogue Decomposition Using Thermal Desorption Coupled to Comprehensive Two-Dimensional Gas Chromatography-Time-of-Flight Mass Spectrometry
Stefanuto, Pierre-Hugues ULg; Stadler, Sonja; Brokl, Michal et al

in Analytical Chemistry (2013), 85(2), 998-1005

Complex processes of decomposition produce a variety of chemicals as soft tissues, and their component parts are broken down. Among others, these decomposition byproducts include volatile organic ... [more ▼]

Complex processes of decomposition produce a variety of chemicals as soft tissues, and their component parts are broken down. Among others, these decomposition byproducts include volatile organic compounds (VOCs) responsible for the odor of decomposition. Human remains detection (HRD) canines utilize this odor signature to locate human remains during police investigations and recovery missions in the event of a mass disaster. Currently, it is unknown what compounds or combinations of compounds are recognized by the HRD canines. Furthermore, a comprehensive decomposition VOC profile remains elusive. This is likely due to difficulties associated with the nontarget analysis of complex samples. In this study, cadaveric VOCs were collected from the decomposition headspace of pig carcasses and were further analyzed using thermal desorption coupled to comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (TD-GC × GC−TOFMS). Along with an advanced data handling methodology, this approach allowed for enhanced characterization of these complex samples. The additional peak capacity of GC × GC, the spectral deconvolution algorithms applied to unskewed mass spectral data, and the use of a robust data mining strategy generated a characteristic profile of decomposition VOCs across the various stages of soft-tissue decomposition. The profile was comprised of numerous chemical families, particularly alcohols, carboxylic acids, aromatics, and sulfides. Characteristic compounds identified in this study, e.g., 1-butanol, 1-octen-3-ol, 2-and 3-methyl butanoic acid, hexanoic acid, octanal, indole, phenol, benzaldehyde, dimethyl disulfide, and trisulfide, are potential target compounds of decomposition odor. This approach will facilitate the comparison of complex odor profiles and produce a comprehensive VOC profile for decomposition. [less ▲]

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See detailTime-Controlled Cryogenic Zone Compression (tCZC) GC-HRMS, A Novel Tool fro Targetted Analysis at Uktra Trace Level
Krumwiede, D; Mehmlann, H; Focant, Jean-François ULg et al

in Organohalogen Compounds (2013), 75

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See detailEffects of a sublethal pesticide exposure on locomotor behavior: A video-tracking analysis in larval amphibians
Denoël, Mathieu ULg; Libon, Sylvie; Kestemont, Patrick et al

in Chemosphere (2013), 90(3), 945-951

Organochlorine pesticides such as endosulfan have been shown to have both lethal and sublethal effects on amphibians. In this context, behavioral endpoints have proved their usefulness in evidencing ... [more ▼]

Organochlorine pesticides such as endosulfan have been shown to have both lethal and sublethal effects on amphibians. In this context, behavioral endpoints have proved their usefulness in evidencing impacts of such chemicals at environmental concentrations that do not necessarily cause mortality. The recent development of video-tracking technologies now offers the possibility of accurately quantifying locomotor behaviors. However, these techniques have not yet been applied to evaluating the toxicity of pesticides in amphibians. We therefore aimed at determining the potential toxicity of endosulfan on endpoints associated with locomotion after short-term environmental endosulfan exposure in Rana temporaria tadpoles and at using these data as warning systems for survival alterations after a longer exposure. To this end, we analyzed video-tracks of 64 tadpoles (two pesticide treatments: 5 and 50 μg L−1, one control and one solvent-control) with Ethovision XT 7 software. The highest endosulfan concentration had a significant effect on all four behavioral endpoints. Contaminated tadpoles traveled shorter distances, swam less often, at a lower mean speed, and occupied a less peripherical position than control tadpoles. The lowest endosulfan concentration had similar but lower effects, and did not affect mean speed during swimming. Survival was reduced only after a long-term exposure to endosulfan and was associated with short-term behavioral dysfunctions. These results show that endosulfan strongly affects the behavioral repertory of amphibian tadpoles, but in different ways depending on concentration, thus suggesting that the pesticide has complex modes of action. Given the importance of locomotion and space use in tadpole success in their aquatic environment, these results confirm the toxic action of endosulfan. By highlighting effects before mortality markers, video-tracking systems also show their potential as sentinels of sublethal effects of pesticides. [less ▲]

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See detailImprovement of Ylang-Ylang Essential Oil Characterization by GCxGC-TOFMS
Brokl, Michal ULg; Fauconnier, Marie-Laure ULg; Benini, Céline et al

in Molecules (2013), 18(2), 1783-1797

A single fraction of essential oil can often contain hundreds of compounds. Despite of the technical improvements and the enhanced selectivity currently offered by the state-of-the-art gas chromatography ... [more ▼]

A single fraction of essential oil can often contain hundreds of compounds. Despite of the technical improvements and the enhanced selectivity currently offered by the state-of-the-art gas chromatography (GC) and mass spectrometry (MS) instruments, the complexity of essential oils is frequently underestimated. Comprehensive two-dimensional GC coupled to time-of-flight MS (GC×GC-TOFMS) was used to improve the chemical characterization of ylang-ylang essential oil fractions recently reported in a previous one-dimensional (1D) GC study. Based on both, the enhanced chromatographic separation and the mass spectral deconvolution, 161 individual compounds were identified and labeled as potentially characteristic analytes found in both low and high boiling fractions issued from distillation of mature ylang-ylang flowers. Compared to the most recent full GC-MS characterization, this represents 75 new compounds, essentially consisting of terpenes, terpenoid esters, and alcohols. [less ▲]

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See detailAnalytical Methodology of POPs
Reiner, EJ; Jobst, KJ; Megson, D et al

in Environmental Forensics: Persistent Organic Pollutants (POPs) (2013)

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See detailScreening and confirmatory methods for the detection of dioxins and polychlorinated biphenyls (PCB) in foods
Focant, Jean-François ULg; Eppe, Gauthier ULg

in Rose, Martin; Fernandes, Alwyn (Eds.) Persistent organic pollutants and toxic metals in foods (2013)

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See detailAnalysis of mainstream tobacco smoke particulate phase using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry
Brokl, Michal ULg; Bishop, L; Wright, C et al

in Journal of Separation Science (2013), 31

In tobacco research, the comparison of different tobacco blends as well as the puffdependent <br />behaviour of cigarettes is a matter of particular interest. For the investigation <br />of smoke ... [more ▼]

In tobacco research, the comparison of different tobacco blends as well as the puffdependent <br />behaviour of cigarettes is a matter of particular interest. For the investigation <br />of smoke characteristics, GC6GC offers different ways for data analysis, <br />namely, compound target analysis, automated peak-based compound classification <br />and comprehensive pixel-based data analysis. This study will show the application <br />as well as the pros and cons of these types of data analysis for very complex matrices <br />like cigarette particulate matter. In addition, new aspects about the recently discovered <br />puff-dependent behaviour of compounds in cigarette smoke will be presented. <br />Automated peak-based compound classification including mass spectrometric pattern <br />recognition is used for the classification of tobacco particulate matter samples <br />and the puff-dependent investigation of different compound classes. This compound <br />group specific analysis is further reinforced by applying an even more comprehensive <br />pixel-based analysis. This kind of analysis is used to generate fingerprints of <br />different types of cigarettes. The combination of fast feature reduction methods like <br />analysis of variance (ANOVA) and t-test with multivariate feature transformation <br />methods like partial least squares discriminate analysis (PLSDA) for feature selection <br />provides a powerful tool for a detailed inspection of different types of cigarettes. [less ▲]

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