References of "De Pauw, Edwin"
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See detailValidation and discussion of CALUX analysis for marine samples
Windal, Isabelle; Van Wouwe, Nathalie; Carbonnelle, Sophie et al

in Organohalogen Compounds (2003)

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See detailSelective adsorption of dioxins and PCBs from marine oils on activated carbon
De Meulenaer, Bruno; Maes, Jeroen; Van Heerswynghels, Peter et al

in Organohalogen Compounds (2003)

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See detailAnalysis of PCDD/Fs in human blood plasma using CALUX bioassay and GC-HRMS: a comparison
Van Wouwe, Nathalie; Eppe, Gauthier ULg; Xhrouet, Céline ULg et al

in Organohalogen Compounds (2003)

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See detailDioxins, furans and dioxin-like PCBs in juvenile harbour porpoises (Phocoena Phocoena) from the North sea
Beans, Cristina; Debacker, Virginie ULg; Jauniaux, Thierry ULg et al

in Organohalogen Compounds (2003)

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See detailThermometer ions for matrix-enhanced laser desorption/ionization internal energy calibration
Greisch, Jean-François ULg; Gabelica, Valérie ULg; Remacle, Françoise ULg et al

in Rapid Communications in Mass Spectrometry : RCM (2003), 17(16), 1847-1854

This work describes a method to use relative fragmentation yields to characterize the internal energy distribution of ions produced by matrix-enhanced laser desorption/ionization mass spectrometry (MELDI ... [more ▼]

This work describes a method to use relative fragmentation yields to characterize the internal energy distribution of ions produced by matrix-enhanced laser desorption/ionization mass spectrometry (MELDI-MS, see: Wright LG, Cooks RG, Wood KL. Biomed. Mass Spectrom. 1985; 12:153162). Assuming that the fragmentation proceeds statistically and that the collisions in the source lead to a Boltzmann-like distribution of the internal energy, a characteristic parameter, the effective temperature, is introduced to describe the internal energy distribution of the ions observed. The hypotheses, advantages and drawbacks of the implementation of the method that uses substituted benzylpyridinium salts as thermometer ions are discussed. Use is made of two matrices that produce no matrix cations in MELDI and are suitable for small cationic salts. The actual value of this effective temperature significantly depends on an accurate determination of the threshold dissociation energies and on the time spent in the source, in addition to the statistical hypothesis itself. The method could be applied to normalize spectra in order to compare results issued from different instruments. [less ▲]

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See detailTelomestatin-induced stabilization of the human telomeric DNA quadruplex monitored by electrospray mass spectrometry
Rosu, Frédéric ULg; Gabelica, Valérie ULg; Shin-ya, Kazuo et al

in Chemical Communications (2003), (21), 2702-2703

Electrospray mass spectrometry (ESI-MS) was used to monitor the kinetics of duplex formation between the human telomeric DNA quadruplex and its complementary strand; the complexation of telomestatin to ... [more ▼]

Electrospray mass spectrometry (ESI-MS) was used to monitor the kinetics of duplex formation between the human telomeric DNA quadruplex and its complementary strand; the complexation of telomestatin to the G-quadruplex delays the unwinding of the quadruplex structure and formation of the duplex. [less ▲]

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See detailDioxins, furans and co-planar PCBs in juvenile harbour porpoises (Phocoena phocoena) from the Belgian coasts
Beans, Cristina ULg; Das, Krishna ULg; Jauniaux, Thierry ULg et al

Poster (2003)

Dioxins, furans and PCBs are lipophilic anthropogenic contaminants that have found their way into marine food webs and accumulate in top predators such as marine mammals, adding a stress factor to an ... [more ▼]

Dioxins, furans and PCBs are lipophilic anthropogenic contaminants that have found their way into marine food webs and accumulate in top predators such as marine mammals, adding a stress factor to an already vulnerable population. In this study 7 congeners of dioxins (PCDDs), 10 congeners of furans (PCDFs) and 4 congeners of coplanar PCBs (cPCBs) were determined using high resolution gas chromatography and mass spectrometry in the blubber of 19 juvenile harbour porpoises (Phocoena phocoena) stranded along the Belgian North Sea coastline between 1995 and 2001. These results were contrasted with nutritional status (emaciated or not), sex and trophic level (through stable carbon and nitrogen isotope analysis). Mean blubber concentrations of SPCDD/Fs were 12.8 pg/g lw (lipid weight) and mean related toxicity 1.84 pg TEQs/g lw (TEQs = TCDD toxic equivalents). Mean cPCB concentrations were 223,5 pg/g lw and mean related toxicity 4,47 pg TEQs/g lw. The levels detected in these individuals were of the same order as those found in a previous study in the Wadden Sea (Bruhn, 1999). Both sexes show rather similar levels. No significant relationship was observed between stable carbon or nitrogen isotope values and pollutant levels. Concentrations and toxicity show a tendency to be higher in emaciated ndividuals than in nonemaciated ones. This could indicate a possible relationship between the nutritional status of the animals and dioxinlike pollutants (which could participate in weakening the animal). This situation should be further studied on adult individuals in order to obtain a more global view of the possible effects on the population. [less ▲]

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See detailCalibration of ion effective temperatures achieved by resonant activation in a quadrupole ion trap
Gabelica, Valérie ULg; Karas, Michael; De Pauw, Edwin ULg

in Analytical Chemistry (2003), 75(19), 5152-5159

The present paper describes a calibration of the ion effective temperatures as a function of the resonant activation amplitude in a quadrupole ion trap mass spectrometer. MS/MS experiments are performed ... [more ▼]

The present paper describes a calibration of the ion effective temperatures as a function of the resonant activation amplitude in a quadrupole ion trap mass spectrometer. MS/MS experiments are performed on leucine enkephalin (M + H)(+), bradykinin (M + H)(+), (M + 2H)(2+), and (M + 3H)(3+), and ubiquitin (M + 11H)(11+). For each amplitude, the effective temperature is calculated as the temperature that would give the same dissociation rate constant as the one observed and is calculated using published Arrhenius parameters. The effective temperature is found to be linearly dependent on the activation amplitude on the range investigated. The dependence of the slope and of the intercept of the T-eff = f (amplitude) functions on the parent ion m/z is examined and an equation is derived to calibrate the ion effective temperature between 365 and 600 K Below 365 K, a deviation from linearity is expected. Above 600 1 the validity of the equation will depend on whether the rapid energy exchange limit is still reached. Calculating backward, the Arrhenius parameters from the measured dissociation rates using this calibration show excellent agreement with the published values. The calibration can therefore be used to determine Arrhenius activation parameters from dissociation kinetics under resonant activation in quadrupole ion trap mass spectrometers. [less ▲]

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See detailFast automated extraction and clean-up of biological fluids for polychlorinated dibenzo-p-dioxins, dibenzofurans and coplanar polychlorinated biphenyls analysis
Focant, Jean-François ULg; De Pauw, Edwin ULg

in Journal of Chromatography. B : Analytical Technologies in the Biomedical & Life Sciences (2002), 776(2), 199-212

A fast automated extraction and clean-up procedure for low-level analysis of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (cPCBs ... [more ▼]

A fast automated extraction and clean-up procedure for low-level analysis of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (cPCBs) in biological fluids is presented. Online extraction of prepared fluids is carried out using disposable octadecyl bonded (C-18) solid-phase extraction columns. Extracts are then cleaned up through disposable multi-layer silica (acidic, basic and neutral) and dispersed PX-21 carbon columns. This new methodology is compared with classical Soxhlet extraction and manual solid-phase extraction in terms of repeatability, reproducibility, accuracy and recovery rates for reference and certified materials. Robustness is evaluated on different matrices, such as cow's milk, breast milk and human serum. As a consequence of the reduced number of reusable glassware used, as well as lowering of solvent consumption, recorded blank levels are decreased in favor of limits of detection (LODs). Total analysis time and cost are further reduced using simultaneous sample preparation units and the sample throughput is increased compared to classical methods. As a result, this new approach appears to be suitable for the fast sample preparation often required for such fluids in case of emergency foodstuffs analysis or during large epidemiological studies. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailLevels and profiles of PCDDs, PCDFs and cPCBs in Belgian breast milk. Estimation of infant intake
Focant, Jean-François ULg; Pirard, Catherine; Thielen, Caroline ULg et al

in Chemosphere (2002), 48(8), 763-770

Congener-specific analyses of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and non-ortho (coplanar) polychlorinated biphenyls (cPCBs) were performed on 20 non-pooled ... [more ▼]

Congener-specific analyses of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and non-ortho (coplanar) polychlorinated biphenyls (cPCBs) were performed on 20 non-pooled breast milk samples collected in or close to an industrial area of Wallonia (Belgium). PCDD/F concentrations ranged between 16.0 and 52.1 pg TEQ/g fat, with a mean value of 29.4 pg TEQ/g fat. If coplanar PCBs (77, 126, 169) are included in TEQ calculations, levels ranged between 22.2 and 100.2 pg TEQ/g fat, with a mean value of 40.8 pg TEQ/g fat. It appears that 2,3,7,8-TCDD, 1,2,3,7,8-PeCDD, 2,3,4,7,8-PeCDF and PCB-126 account for more than 90% of the TEQ. Estimated PCDD/F dietary intake is 76 pg TEQ/kg body weight (bw)/day. This value is almost 20 times higher than the World Health Organization tolerable daily intake. A value of 103 pg TEQ/kg bw/day represents the intake of PCDDs, PCDFs and cPCBs (no mono-ortho PCBs included). (C) 2002 Published by Elsevier Science Ltd. [less ▲]

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See detailLevels and congener distributions of PCDDs, PCDFs and non-ortho PCBs in Belgian foodstuffs - Assessment of dietary intake
Focant, Jean-François ULg; Eppe, Gauthier ULg; Pirard, C. et al

in Chemosphere (2002), 48(2), 167-179

Congener-specific analyses of 7 polychlorinated dibenzo-p-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs) and 4 non-ortho (coplanar) polychlorinated biphenyls (cPCBs) were performed on 197 ... [more ▼]

Congener-specific analyses of 7 polychlorinated dibenzo-p-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs) and 4 non-ortho (coplanar) polychlorinated biphenyls (cPCBs) were performed on 197 foodstuffs samples of animal origin from Belgium during years 2000 and 2001. All investigated matrices (except horse) present background levels lower than the Belgian non-commercialization value of 5 pg TEQ/g fat. Pork was the meat containing the lowest concentration of both PCDD/Fs and cPCBs. The mean background concentration of 2,3,7,8-TCDD toxicity equivalent in milk was 1.1 pg/g of fat, with a congener distribution typical of non-contaminated milk. The relative contribution of 2,3,7,8-TCDD, 2,3,7,8-TCDF, 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF to the PCDD/Fs TEQ was 85 +/- 7.9% for all investigated matrices. The cPCBs contribution to the total TEQ was 47 +/- 19.0% for products of terrestrial species and 69 +/- 20.0% for aquatic species. Once the contribution of cPCBs was added to the TEQ, few foodstuffs such as horse, sheep, beef, eggs and cheese presented levels above the future European guidelines that currently only include PCDD/Fs but will be re-evaluated later in order to include 'dioxin-like' PCBs. Based on levels measured in the samples, the estimation of the dietary intake was 65.3 pg WHO-TEQ/day for PCDD/Fs only (1.00 pg WHO-TEQ/kg bw/day, for a 65 kg person) and 132.9 pg WHO-TEQ/day if cPCBs were included (2.04 pg WHO-TEQ/kg bw/day, for a 65 kg person). Meat (mainly beef), dairy products, and fish each account for roughly one third of the intake. (C) 2002 Elsevier Science Ltd. All rights reserved. [less ▲]

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See detailAspects quantitatifs de la spectrométrie de masse des biomolécules
De Pauw, Edwin ULg; Gabelica, Valérie ULg; Gillet, Marie-Claire ULg et al

Conference (2002, March)

Spectrométrie de masse en 2002 : plus haut, plus vite… mais jusqu’où et pourquoi faire ?

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