References of "Focant, Jean-François"
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See detailDecrease of serum concentrations of dioxins and PCBs in Belgium between 2000 and 2003
Fierens, Sébastien; Heilier, Jean-François; Eppe, Gauthier ULg et al

in Organohalogen Compounds (2005), 67

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See detailMeasurement of Dioxins and WHO-PCBs in Foodstuffs using GCxGC-IDTOFMS
Focant, Jean-François ULg; De Pauw, Edwin ULg

Scientific conference (2004, December)

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See detailMeasurement of selected polybrominated diphenyl ethers, polybrominated and polychlorinated biphenyls, and organochlorine pesticides in human serum and milk using comprehensive two-dimensional gas chromatography isotope dilution time-of-flight mass spectrometry
Focant, Jean-François ULg; Sjodin, Andreas; Turner, Wayman E. et al

in Analytical Chemistry (2004), 76(21), 6313-6320

A new method using comprehensive two-dimensional gas chromatography and isotope dilution time-of-flight mass spectrometry (GC x GC-IDTOFMS) for the simultaneous measurement of selected polychlorinated ... [more ▼]

A new method using comprehensive two-dimensional gas chromatography and isotope dilution time-of-flight mass spectrometry (GC x GC-IDTOFMS) for the simultaneous measurement of selected polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and brominated flame retardants is presented. In contrast to the reference methods based on classical GC/MS, a single injection of the extract containing all compounds of interest results in accurate identification and quantification. Using GC x GC ensures the chromatographic separation of most compounds, and TOFMS allows mass spectral deconvolution of coeluting compounds as well as the use of C-13-labeled internal standards for quantification. Isotope ratio measurements of the most intense ions for both native and labels ensure the required specificity. The use of this new method with an automated sample preparation procedure developed at the Centers for Disease Control and Prevention (CDC) for the analysis of human serum and milk compared favorably to conventional isotope-dilution one-dimensional gas chromatography-high-resolution mass spectrometty (GC-IDHRMS) for the different human serum and milk pools tested. The instrumental detection limits ranged between 0.5 pg/muL and 10 pg/muL and the method detection limits ranged between I and 15 pg/muL (N = 59 analytes). The reproducibility of the method was almost as good as with GC-IDHRMS, the relative standard deviations ranging between 1 and 11% for OCPs measured in human serum. OCP, PBDE, and PCB levels measured using the two methods were highly correlated, and the deviations between the two methods were below 20% for most analytes with concentrations above 1 ng/g milk lipids. [less ▲]

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See detailMeasurement of Halogenated Contaminants in Human Serum and Milk using GCxGC-IDTOFMS
Focant, Jean-François ULg; sjodin; Turner et al

Conference (2004, September)

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See detailMeasurement of PCDDs, PCDFs, and non-ortho-PCBs by comprehensive two-dimensional gas chromatography-isotope dilution time-of-flight mass spectrometry (GC x GC-IDTOFMS)
Focant, Jean-François ULg; Reiner, Eric J.; MacPherson, Karen et al

in Talanta (2004), 63(5), 1231-1240

Comprehensive two-dimensional gas chromatography with isotope-dilution time-of-flight mass spectrometry (GC x GC-IDTOFMS) was used to measure polychlorinated dibenzo-p-dioxin (PCDD), polychlorinated ... [more ▼]

Comprehensive two-dimensional gas chromatography with isotope-dilution time-of-flight mass spectrometry (GC x GC-IDTOFMS) was used to measure polychlorinated dibenzo-p-dioxin (PCDD), polychlorinated dibenzofuran (PCDF), and coplanar polychlorinated biphenyl (cPCB) concentrations in ash, sediment, vegetation, and fish samples. The GC x GC capability was achieved by using a quad jet, dual stage, thermal modulator. Zone compression of the GC peaks from modulation resulted in a significant increase of the signal intensity over classical GC-IDTOFMS. The GC x GC column set used an Rtx-Dioxin 2 phase as the first dimension (D-1) and an Rtx-500 as the second dimension (D-2). The chromatographic separation of the 17 PCDD/Fs and the 4 cPCBs was attained in D-1 except for 2,3,7,8-TCDD and CB126 for which deconvoluted ion currents (DIC) were required to be reported separately. The Rtx-500 phase separated the bulk matrix interfering compounds from the target analytes in D-2. The instrumental limit of detection (iLODs) was 0.5 pg for 2,3,7,8-TCDD. The calibration curves showed good correlation coefficients for all the compounds investigated in the concentration range of 0.5-200 pg. GC x GC-IDTOFMS results compared favorably to those from conventional isotope-dilution one-dimensional gas chromatography-high resolution mass spectrometry (GC-IDHRMS). The comprehensive mass analysis of the TOFMS further permitted the identification of other contaminants of concern in the samples. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailAutomated sample preparation-fractionation for the measurement of dioxins and related compounds in biological matrices: a review
Focant, Jean-François ULg; Pirard, Catherine; De Pauw, Edwin ULg

in Talanta (2004), 63(5), 1101-1113

This article reviews some of the recent developments in the extraction and clean-up areas of biological samples dedicated to dioxin and related compound analysis. A brief introduction on the major dioxin ... [more ▼]

This article reviews some of the recent developments in the extraction and clean-up areas of biological samples dedicated to dioxin and related compound analysis. A brief introduction on the major dioxin contamination events, which have occurred in the food chain, is given to illustrate the need of fast high throughput methods in case of crises. The emphasis of this paper is the method development based upon reliable instrumental extraction techniques for rapid sample processing and automation such as; supercritical fluid extraction (SFE), microwave-assisted extraction (MAE), pressurized liquid extraction (PLE) and, solid-phase extraction (SPE). The PLE and SPE are also discussed in conjunction with the use of a multi-column automated clean-up system that can accommodate up to 5 g of extracted lipids. The fractionation in sub-groups of analytes during the clean-up process allows the isolation of various types of toxicants from a single sample and illustrates the versatility of the system. An integrated extraction and clean-up instrument is finally presented in terms of feasibility and attainable sample turnover for the parallel processing of liquid and solid biological samples. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailPTV-LV-GC/MS/MS as screening and complementary method to HRMS for the monitoring of dioxin levels in food and feed
Eppe, Gauthier ULg; Focant, Jean-François ULg; Pirard, Catherine et al

in Talanta (2004), 63(5), 1135-1146

Recent developments in trapping efficiency inside ion trap mass spectrometer permitted to lower instrument detection limit (IDL). An IDL of 200 fg mul(-1) injected with a signal-to-noise ratio of 5:1 for ... [more ▼]

Recent developments in trapping efficiency inside ion trap mass spectrometer permitted to lower instrument detection limit (IDL). An IDL of 200 fg mul(-1) injected with a signal-to-noise ratio of 5:1 for tetrachlorodibenzo-p-dioxin (TCDD) was obtained by gas chromatography coupled to a quadrupole ion storage mass spectrometer in tandem mode (GC/MS/MS). Coupling large volume programmable temperature vaporizer (PTV-LV) injection to GC/MS/MS provides an alternative and complementary method to classical splitless-GC injection connected to high-resolution mass spectrometry (splitless-GC/HRMS) method for dioxin monitoring in food and feed. An injection volume of 10 mul was found to be the best compromise between the sensitivity requirements and the robustness required for a high throughput method. PTV-LV-GC/MS/MS and Splitless-GC/HRMS were compared by performing analysis on five different matrices such as beef fat, yolk eggs, milk powder, animal feed and serum samples covering a concentration range of two orders of magnitude (i.e. 0.2-25 ng WHO-TEQ kg(-1)). An analysis of variance (ANOVA) was carried out. Fisher tests pointed out that the method effect for all the 2,3,7,8 congeners was not significant, indicating that the null hypothesis (H-0: mu(1) = mu(2) = ... = mu(n)) was not rejected. Moreover, the interaction effects between methods and matrices were not significant for most of the 2,3,7,8 congeners. However, three congeners (2,3,7,8-TCDF; 1,2,3,4,7,8-HxCDD and I,2,3,4,6,7,8-HpCDD) were characterized by P-values lower than the significance level (alpha = 0.05). In toxic equivalence (TEQ), the study showed that no significant bias was observed between the two methods. Consequently, PTV-LV-GC/MS/MS is an attractive technique and can be used as a cost effective complementary method to HRMS for dioxin levels monitoring in food and feed. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailImproved separation of the 209 polychlorinated biphenyl congeners using comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry
Focant, Jean-François ULg; Sjödin, Andreas; Patterson, Donald G.

in Journal of Chromatography. A (2004), 1040(2), 227-238

The separation of the 209 polychlorinated biphenyl (PCB) congeners has been studied using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC x GC-TOFMS). Four ... [more ▼]

The separation of the 209 polychlorinated biphenyl (PCB) congeners has been studied using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC x GC-TOFMS). Four column combinations based on thermally stable phases, DB-1/HT-8, DB-XLB/HT-8, DB-XLB/BPX-50, and HT-8/BPX-50, have been investigated. The HT-8/BPX-50 set produced the best separation. The distribution of the 100 to 150 ms wide peaks was highly structured in the chromatographic space and based on the degree of ortho-substitution within each separated homologue series. A total of 192 congeners were resolved in 146 min (1.3 analyte per min) using this column set. Eight coelutions involved 17 congeners. Among them, seven congeners were present in Aroclors at levels >1.0 wt.% (CBs 33, 47, 48, 95, 97, 163, 187). Except for CBs 47 and 48, none of the major constituents of commercial mixtures were coeluting. CB 138 was well separated from CBs 163 and 164 in the second dimension. For all column sets, CBs 20, 33, and 109 always coeluted with other PCBs. The 12 toxic dioxin-like congeners (CBs 77, 81, 105, 114, 118, 123, 126, 156, 157, 167, 169, 189), and the seven European Union marker PCBs (CBs 28, 52, 101, 118, 138, 153, 180) were separated from any interfering congeners. This was not the case for the other investigated column sets. [less ▲]

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See detailConcentration of Polybrominated Diphenyl Ethers (PBDEs) in House Hold Dust – Inhalation a Potential Route of Human Exposure.
sjodin; Papke; Mc Gahee et al

Poster (2004, June)

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See detailAutomated extraction and clean-up system for liquid materials
Focant, Jean-François ULg; De Pauw, Edwin ULg

Scientific conference (2004, April)

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See detailAutomated extraction and clean-up system for solid materials
Focant, Jean-François ULg; De Pauw, Edwin ULg

Scientific conference (2004, April)

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See detailLevels of PCDDs, PCDFs and PCBs in Belgian and international fast food samples
Focant, Jean-François ULg; Pirard, Catherine; De Pauw, Edwin ULg

in Chemosphere (2004), 54(1), 137-142

Congener-specific analyses of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) were performed on twenty-eight non-pooled fast food ... [more ▼]

Congener-specific analyses of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) were performed on twenty-eight non-pooled fast food samples collected in Belgium, Switzerland, Czech Republic, United States of America and Australia. PCDD/F and PCB concentrations for the four investigated types of meals were very low. PCDD/F values ranged from non-detected to 1.40 pg WHO-TEQ/g fat and from 0.79 to 2.08 pg WHO-TEQ/g fat for lower and upper bound, respectively. Major contributors to the PCDD/F TEQ were 1,2,3,4,7,8-HxCDD, 1,2,3,6,7,8-HxCDD, 2,3,7,8-TCDF and 2,3,4,7,8-PeCDF. The relative contribution of PCBs to the total TEQ was 68%. For adults, an average estimated intake was 6.7 pg WHO-TEQ/kg bw/month, including consumption of all types of analyzed meals, representing 9.5% of the PTMI. For child, a value of 14.5 pg WHO-TEQ/kg bw/month was obtained, representing 20.6% of the PTMI. (C) 2003 Elsevier Ltd. All rights reserved. [less ▲]

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