Extraction de composés hydrophiles non ionisables des eaux par entraînement à la vapeur suivi d'une rétention sur résine XAD-4

L'efficacité de l'extraction sur résine XAD-4 a été étudiée à partir de neuf composés hydrophiles non ionisables (alcools, aldéhydes, cétones, esters). Le facteur de capacité (k') est déterminé expérimentalement par élution frontale de différentes fractions volumiques de méthanol. Les rendements de récupération sont évalués pour quatre solvants. L'efficacité maximale et le facteur de concentration optimal sont définis en fonction du volume de percolation et du volume d'élution. Le rendement moyen est de 80 % après élution par l'acétone.L'entraînement dynamique à la vapeur est par ailleurs développé pour concentrer les composés dans 200 ml de distillat à partir de 4 litres d'échantillon. Le rendement moyen est de 77 %. Ces deux techniques sont associées afin d'accroître la spécificité de la méthodologie analytique vis-à-vis des composés hydrophiles non ionisables. Après un entraînement de l'échantillon d'eau, le condensat est ensuite percolé sur une colonne de résine XAD-4 (7 cm x 1,5 cm), l'élution s'effectuant par 14 ml d'acétone. L'éluat est alors concentré, à température ambiante, par un courant d'azote jusqu'à 4 ml, puis analysé par un chromatographe en phase gazeuse. Cette méthodologie a été appliquée à un eau naturelle artificiellement polluée par 15 composés hydrophiles non ionisables. Les rendements de récupération sont compris entre 42 % et 83 % (rendement moyen de 63 %).Non-ionic hydrophilic compounds are very often used as solvents in industrial activities or for domestic use. These products are generally alcohols, aldehydes, ketones and esters. Although they are not very dangerous for the environment at low concentrations, for hazardous pollution conditions there is a need to be able to identify and quantify such compounds. Chlorination of humic substances during drinking water treatment can also generate chlorinated by-products (chlorinated ketones).Because of their solubility in water, it is necessary to concentrate and extract these compounds before gas chromatography analysis. In this study, we describe a method where liquid/gas (steam distillation) and liquid/solid (XAD-4 resin) extractions were combined. The aim of this work was to define analytical conditions to obtain the best efficiency for the overall method.In the first phase, we developed the liquid/solid extraction on XAD-4 resin by studying capacity factors, elution volumes and percolated water volumes. The sorption of nine non- ionic hydrophilic compounds (ethanol, butanol-1, pentanol-1, ethyl acetate, n-butyl acetate, methylisobutylketone, cyclohexanone, diisobutylketone, butanal) from water onto microparticulate XAD-4 resin, and their subsequent recovery into water-methanol mixtures, was used to estimate the capacity factor (k'water) for each analyte. According to the capacity factor values, we could define three classes of compounds:1. highly hydrophilic compounds such as ethanol, which were not very well retained by the resin (k'water=11); 2. moderately hydrophilic compounds such as ethyl acetate, butanol-1, butanal, pentanol-1 for which capacity factors were less than 100; 3. weakly hydrophilic compounds that were well retained by the resin, such as diisobutylketone with a capacity factor equal to 1770. Subsequently, mobilization/recovery by frontal elution into each of four different solvents (dichloromethane, acetone, acetonitrile, methanol) was studied in order to define for each of the analytes an optimal recovery procedure. Recoveries were dependent on the volume of the water sample passing through the column (100 mL, 200 mL, 400 mL) and on volume of solvent used for the elution. The best recoveries were observed when 200 mL of water were passed through the column and when the elution was performed by 14 mL of acetone. Mean recovery was 80%. Methylisobutylketone, pentanol-1 and ethyl acetate were extracted with yields higher than 80%, whereas butanal and 2,2-dichloroethanol showed a poor recovery of around 60%.In the second phase of the study, steam distillation was also assessed as a technique for the concentration of analytes (200 mL condensate from 4 litres aqueous sample). Mean recovery was 77%. Higher recoveries were observed for ethyl acetate, butanol-1, pentanol-1 and 1,1- dichloroacetone. Dichloroethanol was not extracted with a suitable recovery (yield around 33%).The two extraction methods were combined to increase the extraction specificity for non- ionic hydrophilic compounds. In a preliminary concentration step, the analytes were recovered by steam distillation from 4 litre water samples. Analytes were sorbed from the condensate onto a 7 cm x 1.5 cm column of XAD-4 resin, then eluted with 14 mL acetone. The column eluate was concentrated to 4 mL, at room temperature in a gentle stream of nitrogen, and analyzed by gas chromatography.The extraction procedure was applied to 18 compounds (butanol-1, pentanol-1, hexanol-1, octanol-1, decanol, 2,2-dichloroethanol, ethyl acetate, n-butyl acetate, methyl hexanoate, methyl octanoate, methylisobutylketone, diisobutylketone, 1,1-dichloroacetone, octanone-2, butanal, hexanal, octanal, benzaldehyde) in spiked ultrapure water and also to 15 compounds (same compounds except for benzaldehyde and 2,2-dichloroethanol) in spiked natural water. Mean recovery percentages for the analytes in ultrapure water and in natural water were respectively around 60% and 63%. These results demonstrate that the ionic composition of the water medium did not interfere with the efficiency of the complete method. In the case of spiked natural water, recovery yields ranged between 42% (butanol- 1) and 83% (octanol-1).Keywords

Assessment of VOCs Material/Air Exchanges of Building Products Using the DOSEC®-SPME Method

ACTInternational audienceUsing low emissive materials in building is an effective way to reduce indoor concentrations of pollutants such as VOCs. Material emissions are assessed by the ISO 16000-9 standard. This procedure is time-consuming and is not suitable for on-site measurements. This work aimed in assessing an alternative method, DOSEC\textregistered-SPME, for simple measurements. To validate it, emissions of 30 materials were characterized by both ISO 16000-9 and DOSEC\textregistered-SPME. A first correlation was found between the two methods for formaldehyde emissions of raw materials. This encouraging result allows considering the development of new decision making tools for the selection of healthy building materials

Chemical degradation of the encapsulation system in flexible PV panel as revealed by infrared and Raman microscopies

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Assessment of volatile organic compounds and aldehydes exchanges at the air/material interface of building products and their assemblies: towards improving selection criteria of building materials

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Assessment of volatile organic compounds and aldehydes exchanges at the air/material interface of building products and their assemblies: towards improving selection criteria of building materials

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2018 rcc-mrx code edition context, overview, on-going developments

International audienceThe 2018 edition of the RCC-MRx Code will be issued, by the end of the 2018, in French and English versions by AFCEN (Association Francaise pour les regles de Conception et de Construction des Materiels des Chaudieres Electro-nucleaires). This Code set up rules applicable to research reactor components (coming from the RCC-MX 2008 developed in the context of the Jules Horowitz Reactor project), and to components operating at high temperature and to the Vacuum Vessel of ITER (coming from the RCC-MR 2007).This edition takes the beneficial of an important feedback of the users, such as Jules Horowitz reactor or Astrid project, but also from ITER and MYRRHA projects. In parallel, in compliance with the EC's objectives and its own policy of openness, AFCEN proposes to make its codes evolve, taking into account the needs and expectations of European stakeholders (operators, designers, constructors, suppliers) threw a workshop called CWA phase 2. The end of the workshop, planned for 2018, allowed to integrate recommendations issued from this work. This paper gives an overview of the realized work and also identifies the work to be done for an development of a standard such as RCC-MRx code

DOSEC-SPME : a new technique to assess the VOC emission of material

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New methodology for determination of formaldehyde sorption rate constants for selected building materials of indoor surfaces

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