Claude Guillou - Academia.edu (original) (raw)

Papers by Claude Guillou

Research paper thumbnail of Untargeted metabolomics in human health risk assessment of nanoparticles: Data processing workflow challenges

Toxicology Letters, 2013

ABSTRACT Consumers are potentially exposed to nanomaterials during the use of consumer products. ... more ABSTRACT Consumers are potentially exposed to nanomaterials during the use of consumer products. Emerging approaches in the area of assessment of human health effects combine the use of in vitro cell systems and -omics approaches. Metabolomics is complementary to the other -omics disciplines and the combination of these approaches (e.g. proteomics and metabolomics) may provide important information about the status of a cell and unique insights into metabolic dynamics (metabolite changes over time). Analysis of the metabolome is challenging, not least because of the chemical diversity of cellular metabolites, as well as the redundancy of cellular metabolic pathways that complicate data elaboration and interpretation. Progress in metabolomic data processing, however, lags considerably behind that of the other -omics disciplines. Our work aims at bringing metabolomics to a similar “standard” as the other large -omics disciplines by working on the workflow for LC–MS data processing as well as on data management. We have contributed to the development of R scripts that call XCMS to setup a workflow of LC–MS metabolic data processing. XCMS is a modular, open source and platform independent data processing pipeline (http://metlin.scripps.edu/xcms/). The flexibility of R-XCMS based programmes allows us to keep track of all operations in the workflow. This work was carried out as a feasibility study for implementation of LC/MS metabolomic workflows.Weapplied an “untargeted” LC–MS-based approach and chose here to investigate the modification in the metabolome of Caco-2 cell line (as a model of the intestinal barrier) after exposure to gold nanoparticles (AuNPs).

Research paper thumbnail of Application of deuterium NMR and isotopic analysis to the characterization of foods and beverages

Trends in Food Science & Technology, 1991

Abstract The adulteration of expensive commodities such as alcoholic beverages and flavouring mat... more Abstract The adulteration of expensive commodities such as alcoholic beverages and flavouring materials is a costly type of economic fraud, when successful. In many cases, the process of adulteration has become so sophisticated that conventional means of detecting ...

Research paper thumbnail of 1H NMR-Based Protocol for the Detection of Adulterations of Refined Olive Oil with Refined Hazelnut Oil

A 1 H NMR analytical protocol for the detection of refined hazelnut oils in admixtures with refin... more A 1 H NMR analytical protocol for the detection of refined hazelnut oils in admixtures with refined 17 olive oils is reported according to ISO format. The main purpose of this research activity is to 18 suggest a novel analytical methodology easily usable by operators with a basic knowledge of NMR 19 spectroscopy. The protocol, developed on 92 oil samples of different origins within the European 20 MEDEO project, is based on 1 H NMR measurements combined with a suitable statistical analysis. It 21 was developed using a 600 MHz instrument and was tested by two independent laboratories on 22 600 MHz spectrometers, allowing detection down to 10% adulteration of olive oils with refined 23 hazelnut oils. Finally, the potential and limitations of the protocol applied on spectrometers operating 24 at different magnetic fields, that is, at the proton frequencies of 500 and 400 MHz, were 25 investigated. 26 27 KEYWORDS: Hazelnut oil; olive oil; NMR; statistical analysis 28 45 and tocotrienols (6), and on the difference between theoretical 46

Research paper thumbnail of Preface

Research paper thumbnail of Use of pyrolysis–mass spectrometry in food analysis: applications in the food analysis laboratory of the European Commissions’ Joint Research Centre

Journal of Analytical and Applied Pyrolysis, 1999

Pyrolysis–mass spectrometry (Py–MS) is an analytical fingerprinting technique, that offers distin... more Pyrolysis–mass spectrometry (Py–MS) is an analytical fingerprinting technique, that offers distinct advantages in the field of food analysis. The sample is quickly decomposed at several hundred degrees Celsius and the resulting fragments are analysed by mass spectrometry. The mass spectra are subsequently submitted to multivariate data analysis. Py–MS was successfully applied to the determination of the geographical origin of cocoa

Research paper thumbnail of Determination of the geographical origin of green coffee by principal component analysis of carbon, nitrogen and boron stable isotope ratios

Rapid Communications in Mass Spectrometry, 2005

In this study we show that the continental origin of coffee can be inferred on the basis of coupl... more In this study we show that the continental origin of coffee can be inferred on the basis of coupling the isotope ratios of several elements determined in green beans. The combination of the isotopic fingerprints of carbon, nitrogen and boron, used as integrated proxies for environmental conditions and agricultural practices, allows discrimination among the three continental areas producing coffee (Africa, Asia and America). In these continents there are countries producing 'specialty coffees', highly rated on the market that are sometimes mislabeled further on along the export-sale chain or mixed with cheaper coffees produced in other regions. By means of principal component analysis we were successful in identifying the continental origin of 88% of the samples analyzed. An intra-continent discrimination has not been possible at this stage of the study, but is planned in future work. Nonetheless, the approach using stable isotope ratios seems quite promising, and future development of this research is also discussed.

Research paper thumbnail of Policy recommendations and cost implications for a more sustainable framework for European human biomonitoring surveys

Environmental research, Jan 16, 2014

The potential of Human Biomonitoring (HBM) in exposure characterisation and risk assessment is we... more The potential of Human Biomonitoring (HBM) in exposure characterisation and risk assessment is well established in the scientific HBM community and regulatory arena by many publications. The European Environment and Health Strategy as well as the Environment and Health Action Plan 2004-2010 of the European Commission recognised the value of HBM and the relevance and importance of coordination of HBM programmes in Europe. Based on existing and planned HBM projects and programmes of work and capabilities in Europe the Seventh Framework Programme (FP 7) funded COPHES (COnsortium to Perform Human Biomonitoring on a European Scale) to advance and improve comparability of HBM data across Europe. The pilot study protocol was tested in 17 European countries in the DEMOCOPHES feasibility study (DEMOnstration of a study to COordinate and Perform Human biomonitoring on a European Scale) cofunded (50%) under the LIFE+ programme of the European Commission. The potential of HBM in supporting and ...

Research paper thumbnail of NMR determination of absolute site-specific natural isotope ratios of hydrogen in organic molecules. Analytical and mechanistic applications

Research paper thumbnail of The use of stable isotope ratio analyses to discriminate wild and farmed gilthead sea bream (Sparus aurata)

Rapid Communications in Mass Spectrometry, 2007

Continuous flow isotope ratio mass spectrometry (CF-IRMS) has been used to analyze samples of gil... more Continuous flow isotope ratio mass spectrometry (CF-IRMS) has been used to analyze samples of gilthead sea bream (g.s.b.) (Sparus aurata) of known geographical origin (four countries on the Mediterranean Sea) from wild and farmed sources (40 farmed and 10 wild). delta(13)C and delta(15)N values have been measured on muscle samples as these are the most informative parameters of the diet of the animals. Both stable isotopes are indicators of the origin of the fish: delta(13)C giving a tool to distinguish between wild and farmed g.s.b. and delta(15)N being more informative on the geographical origin of the fish (this fact could be related more to differences in feed mixtures given to farmed fish than to geographical reasons). The proposed methodology offers a cost- and time-effective alternative to other analytical techniques in identifying wild and farmed fish.

Research paper thumbnail of Analysis of the13C natural abundance of CO2 gas from sparkling drinks by gas chromatography/combustion/isotope ratio mass spectrometry

Rapid Communications in Mass Spectrometry, 2005

A simple and rapid method to measure naturally occurring d 13 C values of headspace CO 2 of spark... more A simple and rapid method to measure naturally occurring d 13 C values of headspace CO 2 of sparkling drinks has been set up, using direct injections on a gas chromatograph coupled to an isotope ratio mass spectrometer, through a combustion interface (GC/C/IRMS). We tested the method on CO 2 gas from several origins. No significant isotopic fractionation was observed nor influences by secondary compounds eventually present in the gas phase. Standard deviation for these measurements was found to be <0.1%.

Research paper thumbnail of 13C and18O isotopic analysis to determine the origin ofL-tartaric acid

Rapid Communications in Mass Spectrometry, 2005

Due to the ever-increasing amount of attention paid to the &#39;naturalness&#39; of ingre... more Due to the ever-increasing amount of attention paid to the &#39;naturalness&#39; of ingredients in food and beverages by both consumers and controlling authorities, the search for suitable methods for the characterisation of origin is of primary importance. Within the European Community the wine production industry is often faced with the problem of origin control of tartaric acid. This has led to the decision that only L-tartaric acid extracted from grapes (therefore natural) should be used. In order to implement these regulations, a screening of different techniques has been carried out to assess the methodology that best identifies the origin of the tartaric acid. It has already been indicated in previous scientific literature that isotope ratio mass spectrometry is an ideal technique for this type of identification. In this paper we present the results obtained for the measurement of the isotope ratios of carbon-13 and oxygen-18 of natural and synthetic samples of L-tartaric acid considering also natural samples of different geographical origin and years of production.

Research paper thumbnail of Inter-laboratory comparison of elemental analysis and gas chromatography/combustion/isotope ratio mass spectrometry. II. δ 15 N measurements of selected compounds for the development of an isotopic Grob test

Rapid Communications in Mass Spectrometry, 2009

Inter-laboratory comparison of elemental analysis and gas chromatography/combustion/isotope ratio... more Inter-laboratory comparison of elemental analysis and gas chromatography/combustion/isotope ratio mass spectrometry. II. d 15 N measurements of selected compounds for the development of an isotopic Grob test An inter-laboratory exercise was carried out by a consortium of five European laboratories to establish a set of compounds, suitable for calibrating gas chromatography/combustion/isotope ratio mass spectrometry (GC-C-IRMS) devices, to be used as isotopic reference materials for hydrogen, carbon, nitrogen and oxygen stable isotope measurements. The set of compounds was chosen with the aim of developing a mixture of reference materials to be used in analytical protocols to check for food and beverage authentication. The exercise was organized in several steps to achieve the certification level: the first step consisted of the a priori selection of chemical compounds on the basis of the scientific literature and successive GC tests to set the analytical conditions for each single compound and the mixture. After elimination of the compounds that turned out to be unsuitable in a multi-compound mixture, some additional oxygen-and nitrogen-containing substances were added to complete the range of calibration isotopes. The results of d 13 C determinations for the entire set of reference compounds have previously been published, while the dD and d 18 O determinations were unsuccessful and after statistical analysis of the data the results did not reach the level required for certification. In the present paper we present the results of an inter-laboratory exercise to identify and test the set of nitrogen-containing compounds present in the mixture developed for use as reference materials for the validation of GC-C-IRMS analyses in individual laboratories.

Research paper thumbnail of Stable isotopes to discriminate lambs fed herbage or concentrate both obtained from C 3 plants

Rapid Communications in Mass Spectrometry, 2008

This study was aimed at determining whether isotopic ratio mass spectrometry (IRMS) enables us to... more This study was aimed at determining whether isotopic ratio mass spectrometry (IRMS) enables us to discriminate between lambs fed herbage or concentrate, both obtained from C 3 plants, and those fed a concentrate obtained from C 4 plants. Thirty-four Comisana male lambs (age 45 days) were assigned to three feeding treatments. Fourteen lambs were fed vetch (Vicia sativa) ad libitum. Another fourteen lambs received a barley-based concentrate. The remaining six lambs were fed a maize-based concentrate. After 60 days of experimental treatment the animals were slaughtered and the wool, perirenal fat and muscle longissimus dorsi were sampled. The d 13 C and d 15 N values of the muscle, wool and feed were measured by continuous flow elemental analysis (CF-EA)-IRMS. The d 13 C of the fat was determined likewise. The isotopic composition of the tissues reflected that of the three diets. For the lambs which were fed herbage the muscle d 13 C values were higher (P < 0.0005) and d 15 N values were lower (P < 0.0005) than those of the lambs receiving concentrates. The d 15 N and d 13 C values in the muscle and d 13 C values in the adipose tissue allowed perfect discrimination between the lambs fed the three different diets. The regression between the d 13 C values measured in muscle and in wool of lambs was linear (R 2 ¼ 0.99; P < 0.0005). This result shows that d 13 C measured in the wool can predict muscle d 13 C distribution, suggesting that wool is a valuable matrix for meat authentication. means within the same row differ (P < 0.05).

Research paper thumbnail of Oxygen-18 measurement by continuous flow pyrolysis/isotope ratio mass spectrometry of vegetable oils

Rapid Communications in Mass Spectrometry, 1998

ABSTRACT Stable isotopes are now increasingly used for the control of the origin or authenticity ... more ABSTRACT Stable isotopes are now increasingly used for the control of the origin or authenticity of food products. Among these techniques, the measurement of the 18O content of organic compounds has rarely been carried out because of technical difficulties in the preparation and measurement of the samples. Recently a few laboratories have worked on the setting up of on-line methods to allow easier access to the information that can be obtained from 18O/16O ratios. In this work, such a technique was developed by modifying an elemental analyser device for carrying out the pyrolysis of organic matter. This device is coupled to an isotope ratio mass spectrometer for 18O determination in the CO resulting from the pyrolysis of the compound to be analysed, with good results. The relationship between the 18O content of various oils and their geographical origins is discussed. © 1998 John Wiley &amp; Sons, Ltd.

Research paper thumbnail of The intramolecular 13C-distribution in ethanol reveals the influence of the CO2-fixation pathway and environmental conditions on the site-specific 13C variation in glucose

Plant, Cell & Environment, 2011

Efforts to understand the cause of 12 C versus 13 C isotope fractionation in plants during photos... more Efforts to understand the cause of 12 C versus 13 C isotope fractionation in plants during photosynthesis and postphotosynthetic metabolism are frustrated by the lack of data on the intramolecular 13 C-distribution in metabolites and its variation with environmental conditions. We have exploited isotopic carbon-13 nuclear magnetic resonance ( 13 C NMR) spectrometry to measure the positional isotope composition (d 13 Ci, ‰) in ethanol samples from different origins: European wines, liquors and sugars from C3, C4 and crassulacean acid metabolism (CAM) plants. In C3-ethanol samples, the methylene group was always 13 C-enriched (~2‰) relative to the methyl group. In wines, this pattern was correlated with both air temperature and d 18 O of wine water, indicating that water vapour deficit may be a critical defining factor. Furthermore, in C4-ethanol, the reverse relationship was observed (methylene-C relatively 13 Cdepleted), supporting the concept that photorespiration is the key metabolic process leading to the 13 C distribution in C3-ethanol. By contrast, in CAM-ethanol, the isotopic pattern was similar to but stronger than C3-ethanol, with a relative 13 C-enrichment in the methylene-C of up to 13‰. Plausible causes of this 13 C-pattern are briefly discussed. As the intramolecular -values in ethanol reflect that in source glucose, our data point out the crucial impact on the ratio of metabolic pathways sustaining glucose synthesis.

Research paper thumbnail of 1H NMR as a tool for the analysis of mixtures of virgin olive oil with oils of different botanical origin

Magnetic Resonance in Chemistry, 2000

1 H NMR spectroscopy provides a possible alternative to conventional chromatographic methods for ... more 1 H NMR spectroscopy provides a possible alternative to conventional chromatographic methods for determining the composition of oils. In this study, various oils from olive, hazelnut and sunflower were analysed by 1 H NMR spectroscopy. Experimental conditions were chosen in order to have a short experimental time. It was demonstrated that multivariate statistical methods, in particular discriminant analysis, applied to selected predominant peaks in the 1 H NMR spectra of oils resulted in a good separation between these three oils of different botanical origin and permitted the detection of their mixtures.

Research paper thumbnail of Inter-laboratory comparison of elemental analysis and gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS). Part I: δ13C measurements of selected compounds for the development of an isotopic Grob-test

Journal of Mass Spectrometry, 2007

Research paper thumbnail of Determination of the 13 C Content of Glycerol Samples of Different Origin

Journal of Agricultural and Food Chemistry, 1998

The average carbon isotope value (delta(13)C) of 63 samples of glycerol from over 30 different so... more The average carbon isotope value (delta(13)C) of 63 samples of glycerol from over 30 different sources has been determined. The results indicate that it is possible to distinguish the glycerol obtained from the glycerides produced in plants following C-3 and C-4 carbon fixation pathways. The samples obtained from animal sources seem to reflect the composition of the material consumed, as well as that produced by sugar fermentation.

Research paper thumbnail of Virgin Olive Oil Authentication by Multivariate Analyses of 1 H NMR Fingerprints and δ 13 C and δ 2 H Data

Journal of Agricultural and Food Chemistry, 2010

(1)H NMR fingerprints of virgin olive oils (VOOs) from the Mediterranean basin (three harvests) w... more (1)H NMR fingerprints of virgin olive oils (VOOs) from the Mediterranean basin (three harvests) were analyzed by principal component analysis, linear discriminant analysis (LDA), and partial least-squares discriminant analysis (PLS-DA) to determine their geographical origin at the national, regional, or PDO level. Further delta(13)C and delta(2)H measurements were performed by isotope ratio mass spectrometry (IRMS). LDA and PLS-DA achieved consistent results for the characterization of PDO Riviera Ligure VOOs. PLS-DA afforded the best model: for the Liguria class, 92% of the oils were correctly classified in the modeling step, and 88% of the oils were properly predicted in the external validation; for the non-Liguria class, 90 and 86% of hits were obtained, respectively. A stable and robust PLS-DA model was obtained to authenticate VOOs from Sicily: the recognition abilities were 98% for Sicilian oils and 89% for non-Sicilian ones, and the prediction abilities were 93 and 86%, respectively. More than 85% of the oils of both categories were properly predicted in the external validation. Greek and non-Greek VOOs were properly classified by PLS-DA: &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;90% of the samples were correctly predicted in the cross-validation and external validation. Stable isotopes provided complementary geographical information to the (1)H NMR fingerprints of the VOOs.

Research paper thumbnail of Photolysis of α-Tocopherol in Olive Oils and Model Systems

Journal of Agricultural and Food Chemistry, 1998

The photolysis of α-tocopherol (I) in olive oil (O) and in some model systems (n-hexane= H; anhyd... more The photolysis of α-tocopherol (I) in olive oil (O) and in some model systems (n-hexane= H; anhydrous n-hexane= HA, and triolein= T) was studied under sunlight and under artificial light (λ&amp;amp;amp;amp;amp;gt; 290 nm) by HPLC and GC/MS. In O and T, I disappeared linearly to 50% of the ...

Research paper thumbnail of Untargeted metabolomics in human health risk assessment of nanoparticles: Data processing workflow challenges

Toxicology Letters, 2013

ABSTRACT Consumers are potentially exposed to nanomaterials during the use of consumer products. ... more ABSTRACT Consumers are potentially exposed to nanomaterials during the use of consumer products. Emerging approaches in the area of assessment of human health effects combine the use of in vitro cell systems and -omics approaches. Metabolomics is complementary to the other -omics disciplines and the combination of these approaches (e.g. proteomics and metabolomics) may provide important information about the status of a cell and unique insights into metabolic dynamics (metabolite changes over time). Analysis of the metabolome is challenging, not least because of the chemical diversity of cellular metabolites, as well as the redundancy of cellular metabolic pathways that complicate data elaboration and interpretation. Progress in metabolomic data processing, however, lags considerably behind that of the other -omics disciplines. Our work aims at bringing metabolomics to a similar “standard” as the other large -omics disciplines by working on the workflow for LC–MS data processing as well as on data management. We have contributed to the development of R scripts that call XCMS to setup a workflow of LC–MS metabolic data processing. XCMS is a modular, open source and platform independent data processing pipeline (http://metlin.scripps.edu/xcms/). The flexibility of R-XCMS based programmes allows us to keep track of all operations in the workflow. This work was carried out as a feasibility study for implementation of LC/MS metabolomic workflows.Weapplied an “untargeted” LC–MS-based approach and chose here to investigate the modification in the metabolome of Caco-2 cell line (as a model of the intestinal barrier) after exposure to gold nanoparticles (AuNPs).

Research paper thumbnail of Application of deuterium NMR and isotopic analysis to the characterization of foods and beverages

Trends in Food Science & Technology, 1991

Abstract The adulteration of expensive commodities such as alcoholic beverages and flavouring mat... more Abstract The adulteration of expensive commodities such as alcoholic beverages and flavouring materials is a costly type of economic fraud, when successful. In many cases, the process of adulteration has become so sophisticated that conventional means of detecting ...

Research paper thumbnail of 1H NMR-Based Protocol for the Detection of Adulterations of Refined Olive Oil with Refined Hazelnut Oil

A 1 H NMR analytical protocol for the detection of refined hazelnut oils in admixtures with refin... more A 1 H NMR analytical protocol for the detection of refined hazelnut oils in admixtures with refined 17 olive oils is reported according to ISO format. The main purpose of this research activity is to 18 suggest a novel analytical methodology easily usable by operators with a basic knowledge of NMR 19 spectroscopy. The protocol, developed on 92 oil samples of different origins within the European 20 MEDEO project, is based on 1 H NMR measurements combined with a suitable statistical analysis. It 21 was developed using a 600 MHz instrument and was tested by two independent laboratories on 22 600 MHz spectrometers, allowing detection down to 10% adulteration of olive oils with refined 23 hazelnut oils. Finally, the potential and limitations of the protocol applied on spectrometers operating 24 at different magnetic fields, that is, at the proton frequencies of 500 and 400 MHz, were 25 investigated. 26 27 KEYWORDS: Hazelnut oil; olive oil; NMR; statistical analysis 28 45 and tocotrienols (6), and on the difference between theoretical 46

Research paper thumbnail of Preface

Research paper thumbnail of Use of pyrolysis–mass spectrometry in food analysis: applications in the food analysis laboratory of the European Commissions’ Joint Research Centre

Journal of Analytical and Applied Pyrolysis, 1999

Pyrolysis–mass spectrometry (Py–MS) is an analytical fingerprinting technique, that offers distin... more Pyrolysis–mass spectrometry (Py–MS) is an analytical fingerprinting technique, that offers distinct advantages in the field of food analysis. The sample is quickly decomposed at several hundred degrees Celsius and the resulting fragments are analysed by mass spectrometry. The mass spectra are subsequently submitted to multivariate data analysis. Py–MS was successfully applied to the determination of the geographical origin of cocoa

Research paper thumbnail of Determination of the geographical origin of green coffee by principal component analysis of carbon, nitrogen and boron stable isotope ratios

Rapid Communications in Mass Spectrometry, 2005

In this study we show that the continental origin of coffee can be inferred on the basis of coupl... more In this study we show that the continental origin of coffee can be inferred on the basis of coupling the isotope ratios of several elements determined in green beans. The combination of the isotopic fingerprints of carbon, nitrogen and boron, used as integrated proxies for environmental conditions and agricultural practices, allows discrimination among the three continental areas producing coffee (Africa, Asia and America). In these continents there are countries producing &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;specialty coffees&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;, highly rated on the market that are sometimes mislabeled further on along the export-sale chain or mixed with cheaper coffees produced in other regions. By means of principal component analysis we were successful in identifying the continental origin of 88% of the samples analyzed. An intra-continent discrimination has not been possible at this stage of the study, but is planned in future work. Nonetheless, the approach using stable isotope ratios seems quite promising, and future development of this research is also discussed.

Research paper thumbnail of Policy recommendations and cost implications for a more sustainable framework for European human biomonitoring surveys

Environmental research, Jan 16, 2014

The potential of Human Biomonitoring (HBM) in exposure characterisation and risk assessment is we... more The potential of Human Biomonitoring (HBM) in exposure characterisation and risk assessment is well established in the scientific HBM community and regulatory arena by many publications. The European Environment and Health Strategy as well as the Environment and Health Action Plan 2004-2010 of the European Commission recognised the value of HBM and the relevance and importance of coordination of HBM programmes in Europe. Based on existing and planned HBM projects and programmes of work and capabilities in Europe the Seventh Framework Programme (FP 7) funded COPHES (COnsortium to Perform Human Biomonitoring on a European Scale) to advance and improve comparability of HBM data across Europe. The pilot study protocol was tested in 17 European countries in the DEMOCOPHES feasibility study (DEMOnstration of a study to COordinate and Perform Human biomonitoring on a European Scale) cofunded (50%) under the LIFE+ programme of the European Commission. The potential of HBM in supporting and ...

Research paper thumbnail of NMR determination of absolute site-specific natural isotope ratios of hydrogen in organic molecules. Analytical and mechanistic applications

Research paper thumbnail of The use of stable isotope ratio analyses to discriminate wild and farmed gilthead sea bream (Sparus aurata)

Rapid Communications in Mass Spectrometry, 2007

Continuous flow isotope ratio mass spectrometry (CF-IRMS) has been used to analyze samples of gil... more Continuous flow isotope ratio mass spectrometry (CF-IRMS) has been used to analyze samples of gilthead sea bream (g.s.b.) (Sparus aurata) of known geographical origin (four countries on the Mediterranean Sea) from wild and farmed sources (40 farmed and 10 wild). delta(13)C and delta(15)N values have been measured on muscle samples as these are the most informative parameters of the diet of the animals. Both stable isotopes are indicators of the origin of the fish: delta(13)C giving a tool to distinguish between wild and farmed g.s.b. and delta(15)N being more informative on the geographical origin of the fish (this fact could be related more to differences in feed mixtures given to farmed fish than to geographical reasons). The proposed methodology offers a cost- and time-effective alternative to other analytical techniques in identifying wild and farmed fish.

Research paper thumbnail of Analysis of the13C natural abundance of CO2 gas from sparkling drinks by gas chromatography/combustion/isotope ratio mass spectrometry

Rapid Communications in Mass Spectrometry, 2005

A simple and rapid method to measure naturally occurring d 13 C values of headspace CO 2 of spark... more A simple and rapid method to measure naturally occurring d 13 C values of headspace CO 2 of sparkling drinks has been set up, using direct injections on a gas chromatograph coupled to an isotope ratio mass spectrometer, through a combustion interface (GC/C/IRMS). We tested the method on CO 2 gas from several origins. No significant isotopic fractionation was observed nor influences by secondary compounds eventually present in the gas phase. Standard deviation for these measurements was found to be <0.1%.

Research paper thumbnail of 13C and18O isotopic analysis to determine the origin ofL-tartaric acid

Rapid Communications in Mass Spectrometry, 2005

Due to the ever-increasing amount of attention paid to the &#39;naturalness&#39; of ingre... more Due to the ever-increasing amount of attention paid to the &#39;naturalness&#39; of ingredients in food and beverages by both consumers and controlling authorities, the search for suitable methods for the characterisation of origin is of primary importance. Within the European Community the wine production industry is often faced with the problem of origin control of tartaric acid. This has led to the decision that only L-tartaric acid extracted from grapes (therefore natural) should be used. In order to implement these regulations, a screening of different techniques has been carried out to assess the methodology that best identifies the origin of the tartaric acid. It has already been indicated in previous scientific literature that isotope ratio mass spectrometry is an ideal technique for this type of identification. In this paper we present the results obtained for the measurement of the isotope ratios of carbon-13 and oxygen-18 of natural and synthetic samples of L-tartaric acid considering also natural samples of different geographical origin and years of production.

Research paper thumbnail of Inter-laboratory comparison of elemental analysis and gas chromatography/combustion/isotope ratio mass spectrometry. II. δ 15 N measurements of selected compounds for the development of an isotopic Grob test

Rapid Communications in Mass Spectrometry, 2009

Inter-laboratory comparison of elemental analysis and gas chromatography/combustion/isotope ratio... more Inter-laboratory comparison of elemental analysis and gas chromatography/combustion/isotope ratio mass spectrometry. II. d 15 N measurements of selected compounds for the development of an isotopic Grob test An inter-laboratory exercise was carried out by a consortium of five European laboratories to establish a set of compounds, suitable for calibrating gas chromatography/combustion/isotope ratio mass spectrometry (GC-C-IRMS) devices, to be used as isotopic reference materials for hydrogen, carbon, nitrogen and oxygen stable isotope measurements. The set of compounds was chosen with the aim of developing a mixture of reference materials to be used in analytical protocols to check for food and beverage authentication. The exercise was organized in several steps to achieve the certification level: the first step consisted of the a priori selection of chemical compounds on the basis of the scientific literature and successive GC tests to set the analytical conditions for each single compound and the mixture. After elimination of the compounds that turned out to be unsuitable in a multi-compound mixture, some additional oxygen-and nitrogen-containing substances were added to complete the range of calibration isotopes. The results of d 13 C determinations for the entire set of reference compounds have previously been published, while the dD and d 18 O determinations were unsuccessful and after statistical analysis of the data the results did not reach the level required for certification. In the present paper we present the results of an inter-laboratory exercise to identify and test the set of nitrogen-containing compounds present in the mixture developed for use as reference materials for the validation of GC-C-IRMS analyses in individual laboratories.

Research paper thumbnail of Stable isotopes to discriminate lambs fed herbage or concentrate both obtained from C 3 plants

Rapid Communications in Mass Spectrometry, 2008

This study was aimed at determining whether isotopic ratio mass spectrometry (IRMS) enables us to... more This study was aimed at determining whether isotopic ratio mass spectrometry (IRMS) enables us to discriminate between lambs fed herbage or concentrate, both obtained from C 3 plants, and those fed a concentrate obtained from C 4 plants. Thirty-four Comisana male lambs (age 45 days) were assigned to three feeding treatments. Fourteen lambs were fed vetch (Vicia sativa) ad libitum. Another fourteen lambs received a barley-based concentrate. The remaining six lambs were fed a maize-based concentrate. After 60 days of experimental treatment the animals were slaughtered and the wool, perirenal fat and muscle longissimus dorsi were sampled. The d 13 C and d 15 N values of the muscle, wool and feed were measured by continuous flow elemental analysis (CF-EA)-IRMS. The d 13 C of the fat was determined likewise. The isotopic composition of the tissues reflected that of the three diets. For the lambs which were fed herbage the muscle d 13 C values were higher (P < 0.0005) and d 15 N values were lower (P < 0.0005) than those of the lambs receiving concentrates. The d 15 N and d 13 C values in the muscle and d 13 C values in the adipose tissue allowed perfect discrimination between the lambs fed the three different diets. The regression between the d 13 C values measured in muscle and in wool of lambs was linear (R 2 ¼ 0.99; P < 0.0005). This result shows that d 13 C measured in the wool can predict muscle d 13 C distribution, suggesting that wool is a valuable matrix for meat authentication. means within the same row differ (P < 0.05).

Research paper thumbnail of Oxygen-18 measurement by continuous flow pyrolysis/isotope ratio mass spectrometry of vegetable oils

Rapid Communications in Mass Spectrometry, 1998

ABSTRACT Stable isotopes are now increasingly used for the control of the origin or authenticity ... more ABSTRACT Stable isotopes are now increasingly used for the control of the origin or authenticity of food products. Among these techniques, the measurement of the 18O content of organic compounds has rarely been carried out because of technical difficulties in the preparation and measurement of the samples. Recently a few laboratories have worked on the setting up of on-line methods to allow easier access to the information that can be obtained from 18O/16O ratios. In this work, such a technique was developed by modifying an elemental analyser device for carrying out the pyrolysis of organic matter. This device is coupled to an isotope ratio mass spectrometer for 18O determination in the CO resulting from the pyrolysis of the compound to be analysed, with good results. The relationship between the 18O content of various oils and their geographical origins is discussed. © 1998 John Wiley &amp; Sons, Ltd.

Research paper thumbnail of The intramolecular 13C-distribution in ethanol reveals the influence of the CO2-fixation pathway and environmental conditions on the site-specific 13C variation in glucose

Plant, Cell & Environment, 2011

Efforts to understand the cause of 12 C versus 13 C isotope fractionation in plants during photos... more Efforts to understand the cause of 12 C versus 13 C isotope fractionation in plants during photosynthesis and postphotosynthetic metabolism are frustrated by the lack of data on the intramolecular 13 C-distribution in metabolites and its variation with environmental conditions. We have exploited isotopic carbon-13 nuclear magnetic resonance ( 13 C NMR) spectrometry to measure the positional isotope composition (d 13 Ci, ‰) in ethanol samples from different origins: European wines, liquors and sugars from C3, C4 and crassulacean acid metabolism (CAM) plants. In C3-ethanol samples, the methylene group was always 13 C-enriched (~2‰) relative to the methyl group. In wines, this pattern was correlated with both air temperature and d 18 O of wine water, indicating that water vapour deficit may be a critical defining factor. Furthermore, in C4-ethanol, the reverse relationship was observed (methylene-C relatively 13 Cdepleted), supporting the concept that photorespiration is the key metabolic process leading to the 13 C distribution in C3-ethanol. By contrast, in CAM-ethanol, the isotopic pattern was similar to but stronger than C3-ethanol, with a relative 13 C-enrichment in the methylene-C of up to 13‰. Plausible causes of this 13 C-pattern are briefly discussed. As the intramolecular -values in ethanol reflect that in source glucose, our data point out the crucial impact on the ratio of metabolic pathways sustaining glucose synthesis.

Research paper thumbnail of 1H NMR as a tool for the analysis of mixtures of virgin olive oil with oils of different botanical origin

Magnetic Resonance in Chemistry, 2000

1 H NMR spectroscopy provides a possible alternative to conventional chromatographic methods for ... more 1 H NMR spectroscopy provides a possible alternative to conventional chromatographic methods for determining the composition of oils. In this study, various oils from olive, hazelnut and sunflower were analysed by 1 H NMR spectroscopy. Experimental conditions were chosen in order to have a short experimental time. It was demonstrated that multivariate statistical methods, in particular discriminant analysis, applied to selected predominant peaks in the 1 H NMR spectra of oils resulted in a good separation between these three oils of different botanical origin and permitted the detection of their mixtures.

Research paper thumbnail of Inter-laboratory comparison of elemental analysis and gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS). Part I: δ13C measurements of selected compounds for the development of an isotopic Grob-test

Journal of Mass Spectrometry, 2007

Research paper thumbnail of Determination of the 13 C Content of Glycerol Samples of Different Origin

Journal of Agricultural and Food Chemistry, 1998

The average carbon isotope value (delta(13)C) of 63 samples of glycerol from over 30 different so... more The average carbon isotope value (delta(13)C) of 63 samples of glycerol from over 30 different sources has been determined. The results indicate that it is possible to distinguish the glycerol obtained from the glycerides produced in plants following C-3 and C-4 carbon fixation pathways. The samples obtained from animal sources seem to reflect the composition of the material consumed, as well as that produced by sugar fermentation.

Research paper thumbnail of Virgin Olive Oil Authentication by Multivariate Analyses of 1 H NMR Fingerprints and δ 13 C and δ 2 H Data

Journal of Agricultural and Food Chemistry, 2010

(1)H NMR fingerprints of virgin olive oils (VOOs) from the Mediterranean basin (three harvests) w... more (1)H NMR fingerprints of virgin olive oils (VOOs) from the Mediterranean basin (three harvests) were analyzed by principal component analysis, linear discriminant analysis (LDA), and partial least-squares discriminant analysis (PLS-DA) to determine their geographical origin at the national, regional, or PDO level. Further delta(13)C and delta(2)H measurements were performed by isotope ratio mass spectrometry (IRMS). LDA and PLS-DA achieved consistent results for the characterization of PDO Riviera Ligure VOOs. PLS-DA afforded the best model: for the Liguria class, 92% of the oils were correctly classified in the modeling step, and 88% of the oils were properly predicted in the external validation; for the non-Liguria class, 90 and 86% of hits were obtained, respectively. A stable and robust PLS-DA model was obtained to authenticate VOOs from Sicily: the recognition abilities were 98% for Sicilian oils and 89% for non-Sicilian ones, and the prediction abilities were 93 and 86%, respectively. More than 85% of the oils of both categories were properly predicted in the external validation. Greek and non-Greek VOOs were properly classified by PLS-DA: &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;90% of the samples were correctly predicted in the cross-validation and external validation. Stable isotopes provided complementary geographical information to the (1)H NMR fingerprints of the VOOs.

Research paper thumbnail of Photolysis of α-Tocopherol in Olive Oils and Model Systems

Journal of Agricultural and Food Chemistry, 1998

The photolysis of α-tocopherol (I) in olive oil (O) and in some model systems (n-hexane= H; anhyd... more The photolysis of α-tocopherol (I) in olive oil (O) and in some model systems (n-hexane= H; anhydrous n-hexane= HA, and triolein= T) was studied under sunlight and under artificial light (λ&amp;amp;amp;amp;amp;gt; 290 nm) by HPLC and GC/MS. In O and T, I disappeared linearly to 50% of the ...