References of "Pirard, Catherine"
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See detailDoes Imidacloprid Seed-Treated Maize Have an Impact on Honey Bee Mortality?
Nguyen, Bach Kim ULg; Saegerman, Claude ULg; Pirard, Catherine et al

in Journal of Economic Entomology (2009), 102(2), 616-623

Beekeepers suspected maize. Zea mays L., treated with imidacloprid to result in substantial loss of honey bee (Hymenoptera: Apidae) colonies in Belgium. The objective of this study was to investigate the ... [more ▼]

Beekeepers suspected maize. Zea mays L., treated with imidacloprid to result in substantial loss of honey bee (Hymenoptera: Apidae) colonies in Belgium. The objective of this study was to investigate the potential impact of maize grown from imidacloprid-treated seeds on honey bee mortality. A survey of 16 apiaries was carried out, and all maize fields treated or not with imidacloprid were located within a radius of 3,000 m around the observed apiaries. Samples of honey, beeswax, and bees were collected in three colonies per apiary and analyzed for pesticide contain by liquid chromatography-tandem mass spectrometry and gas chromatography-tandem mass spectrometry. We first found significant correlation between the number of colonies per apiary and the mortality rates in an apiary. In addition, this mortality rate was inversely correlated with the surface of maize fields treated and not with imidacloprid, suggesting that this pesticide do not interact with bees fitness. Moreover, a very large number of our samples contained acarcides either prohibited or ineffective against varroa destructor (Anderson & Trueman) (Acari: Varroidae), suggesting that the treatment method used by the beekeepers to be inadequate for mite control. Our results support the hypothesis that imidacloprid seed-treated maize has no negative impact on honey bees. [less ▲]

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See detailDevelopment and validation of a multi-residue method for pesticide determination in honey using on-column liquid-liquid extraction and liquid chromatography-tandem mass spectrometry
Pirard, Catherine; Widart, Joëlle ULg; Nguyen, Bach Kim ULg et al

in Journal of Chromatography. A (2007), 1152(1-2), 116-123

We report on the development and validation under ISO 17025 criteria of a multi-residue confirmatory method to identify and quantify 17 widely chemically different pesticides (insecticides: Carbofuran ... [more ▼]

We report on the development and validation under ISO 17025 criteria of a multi-residue confirmatory method to identify and quantify 17 widely chemically different pesticides (insecticides: Carbofuran, Methiocarb, Pirimicarb, Dimethoate, Fipronil, Imidacloprid; herbicides: Amidosulfuron, Rimsulfuron, Atrazine, Simazine, Chloroturon, Linuron, Isoxaflutole, Metosulam; fungicides: Diethofencarb) and 2 metabolites (Methiocarb sulfoxide and 2-Hydroxytertbutylazine) in honey. This method is based on an on-column liquid liquid extraction (OCLLE) using diatomaceous earth as inert solid support and liquid chromatography (LC) coupled to mass spectrometry (MS) operating in tandem mode (MS/MS). Method specificity is ensured by checking retention time and theoretical ratio between two transitions from a single precursor ion. Linearity is demonstrated all along the range of concentration that was investigated, from 0.1 to 20 ng g(-1) raw honey, with correlation coefficients ranging from 0.921 to 0.999, depending on chemicals. Recovery rates obtained on home-made quality control samples are between 71 and 90%, well above the range defined by the EC/657/2002 document, but in the range we had fixed to ensure proper quantification, as levels found in real samples could not be corrected for recovery rates. Reproducibility is found to be between 8 and 27%. Calculated CC alpha and CC beta (0.0002-0.943 mg g(-1) for CC alpha, and 0.0002-1.232 ng g(-1) for CCP) show the good sensitivity attained by this rnulti-residue analytical method. The robustness of the method has been tested in analyzing more than 100 raw honey samples collected from different areas in Belgium, as well as some wax and bee samples, with a slightly adapted procedure. (C) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailHigh-throughput biomonitoring of dioxins and polychlorinated biphenyls at the sub-picogram level in human serum
Focant, Jean-François ULg; Eppe, Gauthier ULg; Massart, Anne-Cécile ULg et al

in Journal of Chromatography. A (2006), 1130(1), 97-107

We report on the use of a state-of-the-art method for the measurement of selected polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls in human serum specimens ... [more ▼]

We report on the use of a state-of-the-art method for the measurement of selected polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls in human serum specimens. The sample preparation procedure is based on manual small size solid-phase extraction (SPE) followed by automated clean-up and fractionation using multi-sorbent liquid chromatography columns. SPE cartridges and all clean-up columns are disposable. Samples are processed in batches of 20 units, including one blank control (BC) sample and one quality control (QC) sample. The analytical measurement is performed using gas chromatography coupled to isotope dilution high-resolution mass spectrometry. The sample throughput corresponds to one series of 20 samples per day, from sample reception to data quality cross-check and reporting, once the procedure has been started and series of samples keep being produced. Four analysts are required to ensure proper performances of the procedure. The entire procedure has been validated under International Organization for Standardization (ISO) 17025 criteria and further tested over more than 1500 unknown samples during various epidemiological studies. The method is further discussed in terms of reproducibility, efficiency and long-term stability regarding the 35 target analytes. Data related to quality control and limit of quantification (LOQ) calculations are also presented and discussed. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailStudy of the effect of exposition of MCF-7/bos cells to 17-ß-estradiol by 2D DIGE
Collodoro, Mike; Dobson, Rowan ULg; Bertrand, Virginie ULg et al

Poster (2006, October)

The aim of this work is to identify biomarkers following exposition to 17ß-estradiol in MCF7/bos (hormonal dependent epithelial mammary cancer) cells. The application is to optimise screening tests that ... [more ▼]

The aim of this work is to identify biomarkers following exposition to 17ß-estradiol in MCF7/bos (hormonal dependent epithelial mammary cancer) cells. The application is to optimise screening tests that will enable the detection (and eventual quantification but not identification) of numerous compounds having an estrogenic activity in a single rapid test. [less ▲]

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See detailSuitability of tandem-in-time mass spectrometry for polybrominated diphenylether measurement in fish and shellfish samples: Comparison with high resolution mass spectrometry
Pirard, Catherine; De Pauw, Edwin ULg; Focant, Jean-François ULg

in Journal of Chromatography. A (2006), 1115(1-2), 125-132

The first part of the present study focused on the development of an alternative automated sample preparation method for the measurement of selected polybrominated diphenyl ethers (PBDEs) in fish and ... [more ▼]

The first part of the present study focused on the development of an alternative automated sample preparation method for the measurement of selected polybrominated diphenyl ethers (PBDEs) in fish and shellfish. A previously developed automated method has been further optimized and simplified to decrease blank levels and cost. Sorbent and solvent quantities have been significantly reduced without altering extract quality. The second part of the study consisted of comparing tandem-in-time quadrupole ion storage mass spectrometry (QISTMS/MS) to high resolution mass spectrometry (HRMS) for the isotope dilution (ID) measurement step after gas chromatography (GC) separation. Both mass spectrometric methods performed similarly in terms of accuracy but better precision was observed for HRMS. Although better sensitivity can be attained with the high resolution sector instrument, method limits of quantification (mLOQs) were very similar for both approaches as they were dependent on the procedural blanks levels. The mLOQ values ranged between 0.04 and 3.56 ng/g fat, depending on the congener. They allowed the unambiguous identification and quantification of all target analytes, except for BDE-183, in most considered fish extracts. An analytical procedure based on rapid automated sample preparation and QISTMS/MS appeared to be suitable for the measurement of PBDEs in fish and shellfish speciment under quality assurance/quality control (QA/QC) criteria. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailEnvironmental and human impact of an old-timer incinerator in terms of dioxin and PCB level: A case study
Pirard, Catherine; Eppe, Gauthier ULg; Massart, Anne-Cécile ULg et al

in Environmental Science & Technology (2005), 39(13), 4721-4728

The impact of a recently closed old municipal solid waste incinerator (MSWI) on polychlorodibenzo-p-dioxin (POD), polychlorodibenzofuran (PCDF), and polychlorinated biphenyl (PCB) levels in the ... [more ▼]

The impact of a recently closed old municipal solid waste incinerator (MSWI) on polychlorodibenzo-p-dioxin (POD), polychlorodibenzofuran (PCDF), and polychlorinated biphenyl (PCB) levels in the surrounding environment and resident serum has been studied in a small rural area of France. Studied soils and eggs from chickens foraging on these soils were sampled in the vicinity of the MSWI under the prevailing wind stream, while comparison samples were collected outside the assumed impact zone. PCB levels observed in soils and eggs did not differ statistically from comparison sites. This confirmed the low impact of MSWI PCB emission on environmental media, compared to other well-known sources. PCDD/PCDF levels in soils and eggs were significantly higher than in comparison samples, pointing out the impact of MSWI emission on the surrounding environment. The high dioxin concentrations in eggs set aside for private consumption would increase the dioxin intake for the studied population. Blood specimens of 10 nonoccupationally exposed volunteers who had lived within a 2 km radius of the incinerator for at least 25 years have been analyzed. When adjusted for age, PCB and PCDD/F blood levels were higher than general European populations and comparable to a similarly exposed Belgian population. [less ▲]

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See detailRecent advances in mass spectrometric measurement of dioxins
Focant, Jean-François ULg; Pirard, Catherine; Eppe, Gauthier ULg et al

in Journal of Chromatography. A (2005), 1067(1-2), 265-275

Past years, many efforts have been dedicated to the development of alternative analytical methods for the measurement of dioxins in various types of matrices. Polychlorinated dibenzo-p-dioxins (PCDDs ... [more ▼]

Past years, many efforts have been dedicated to the development of alternative analytical methods for the measurement of dioxins in various types of matrices. Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) are compounds that are present in samples at part-per-billion (ppb) or part-per-trillion (ppt) level. Their measurement requires the use of very sensitive analytical methods. Gas chromatography (GC) coupled to quadrupole ion storage mass spectrometry (QISTMS), fast GC (FGC) coupled to time-of-flight mass spectrometry (TOFMS) and comprehensive two-dimensional gas chromatography (GC x GC) coupled to TOFMS are the more promising tools challenging the reference GC high resolution mass spectrometry (HRMS) based on sector instruments. We report herein some of the advances we achieved in the past years in our laboratory on the development of alternative measurement methods for those compounds. (c) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailComprehensive two-dimensional gas chromatography with isotope dilution time-of-flight mass spectrometry for the measurement of dioxins and polychlorinated biphenyls in foodstuffs - Comparison with other methods
Focant, Jean-François ULg; Eppe, Gauthier ULg; Scippo, Marie-Louise ULg et al

in Journal of Chromatography. A (2005), 1086(1-2), 45-60

A comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC x GC-TOF-MS) experimental setup was tested for the measurement of seven 2,3,7,8-substituted polychlorinated dibenzo ... [more ▼]

A comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC x GC-TOF-MS) experimental setup was tested for the measurement of seven 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs), ten 2,3,7,8-substituted polychlorinated dibenzofurans (PCDFs), four non-ortho-polychlorinated biphenyls (PCBs), eight mono-ortho-PCBs, and six indicator PCBs (Aroclor 1260) in foodstuff samples. A 40 m RTX-500 (0.18 mm I.D., 0.10 mu m df) was used as the first dimension (D-1) and a 1.5 nn BPX-50 (0.10 mm I.D., 0.10 mu m df) as the second dimension (2 D). The GC x GC chromatographic separation was completed in 45 min. Quantification was performed using C-13-label isotope dilution (11)). Isotope ratios of the selected quantification ions were checked against theoretical values prior to peak assignment and quantification. The dynamic working range spanned three orders of magnitude. The lowest detectable amount of 2,3,7,8-TCDD was 0.2 pg. Fish, pork, and milk samples were considered. On a congener basis, the GC x GC-ID-TOF-MS method was compared to the reference GC-ID high resolution mass spectrometry (HRMS) method and to the alternative GC-ID tandem-in-time quadrupole ion storage mass spectrometry (QIST-MS/MS). PCB levels ranged from low picogram (pg) to low nanogram (ng) per gram of sample and data compared very well between the different methods. For all matrices, PCDD/Fs were at a low pg level (0.05-3 pg) on a fresh weight basis. Although congener profiles were accurately described, RSDs of GC x GC-ID-TOF-MS and GC-QIST-MS/MS were much higher than for GC-ID-HRMS, especially for low level pork and milk. On a toxic equivalent (TEQ) basis, all methods, including the dioxin-responsive chemically activated luciferase gene expression (DR-CALUX) assay, produced similar responses. A cost comparison is also presented. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailEvaluation of GC-MS/MS for determination of PBDEs in fish and shellfish samples
Pirard, Catherine; Eppe, Gauthier ULg; Massart, Anne-Cécile ULg et al

in Organohalogen Compounds (2005), 67

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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 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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See detailMeasurement of dioxins and WHO PCBs in foodstuffs using GCxGC-IDTOFMs
Focant, Jean-François ULg; Pirard, Catherine; Massart, Anne-Cécile ULg et al

in Organohalogen Compounds (2004), 66

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See detailAssessment of the impact of an old MSWI. Part1 : Level of PCDD/Fs and PCBs in surrounding soils and eggs
Pirard, Catherine; Focant, Jean-François ULg; Massart, Anne-Cécile ULg et al

in Organohalogen Compounds (2004), 66

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See detailSurvey of commercial pasteurised cows' milk in Wallonia (Belgium) for the occurrence of polychlorinated dibenzo-p-dioxins, dibenzofurans and coplanar polychlorinated biphenyls
Focant, Jean-François ULg; Pirard, Catherine; Massart, Anne-Cécile ULg et al

in Chemosphere (2003), 52(4), 725-733

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 35 ... [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 35 samples of commercial long-life pasteurised cows' milk issued from eight different brands available in Walloon supermarkets (Belgium). The observed congener profile was characteristic of milk samples issued from industrialised countries with good inter and intra-brand reproducibility's. The PCDDs to PCDFs ratio was equal to 1.8 in concentration. The toxic equivalent (TEQ based on WHO-TEF) value for PCDD/Fs in all analysed milks was 1.09+/-0.30 pg TEQ/g fat (range 0.86-1.59), which is below the recommended EU non-commercialisation threshold value of 3 pg TEQ PCDD/Fs/g of milk fat. The mean TEQ value including cPCBs was 2.23+/-0.55 pg TEQ/g fat. These PCBs actually contributed for 49+/-8.6% of the total TEQ. Among PCDD/Fs and cPCBs, tetrachloro dibenzo-p-dioxin (TCDD), pentachloro dibenzo-p-dioxin (PeCDD), pentachloro dibenzofurans (PeCDFs) and 3,3',4,4',5-pentachloro biphenyl (PCB-126) were the most important contributors to the TEQ. Estimated daily intake (EDI) due to consumption of such milks was 0.34 pg TEQ/kg of body weight/day for PCDD/Fs and 0.69 pg TEQ/kg of body weight/day when cPCBs were included. [less ▲]

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