Determination of polybromodiphenyl ethers (PBDEs) in milk cream by gas chromatography-mass spectrometry.

International audienceAn analytical method for polybromodiphenyl ethers (PBDEs) in milk cream has been optimized. The six PBDEs targeted were chosen on criteria of toxicity and occurrence in environmental matrices. Three methods of extraction were tested and compared in terms of lipid recovery yields and repeatability. The sample preparation process includes two steps: extraction by accelerated solvent extraction (ASE) and purification by solid phase extraction (SPE). The preferred method of extraction used a hexane/methylene chloride/methanol (5 : 2 : 1, v/v) solvent mixture. Three extraction cycles were carried out per sample at a temperature of 80 degrees C and a pressure of 1500 psi. The method was validated on milk cream samples spiked with the specified PBDEs. Recoveries for the whole sample preparation process (extraction and cleanup) for cream samples spiked at 10 and 100 ng g(-1) were greater than 80% (ranging from 81 to 106%) at both concentrations for BDE-99, -100, -153 and 154. Recoveries were lower (ranging from 65 to 75%) for BDE-28 and BDE-47. PBDEs were quantified by GC/MS detection with selected ion monitoring (SIM) using three ions formed by electron capture. The method was successfully tested on real samples

Le point sur les polybromodiphényléthers : contamination environnementale et méthodes physico-chimiques d'analyse

Les polybromodiphényléthers ou PBDE, utilisés comme retardateurs de flammes dans de nombreux matériaux, ont été récemment interdits en Europe en raison de leur bioaccumulation et de leur toxicité. Cet article décrit de façon non exhaustive le principe de l'action ignifugeante de ces molécules ainsi que leurs utilisations industrielles et leur toxicité. Leur analyse se fait généralement par couplage entre la chromatographie en phase gazeuse et la spectrométrie de masse (CG/SM). Les principales caractéristiques des méthodes de CG/SM sont décrites. Les problèmes posés par l'extraction des PBDE à partir de matrices environnementales ou de fluides biologiques sont également abordés. [Polybromodiphenylethers (PBDE), used as flame retardants in many commercial materials, have been recently forbiden in Europa because of their bioaccumulation and toxicity. This article describes in a non exhaustive manner how these compounds act as flame retardants, their industrial uses and their toxicity. Their analysis is usually performed by coupling gas chromatography with mass spectrometry (GC-MS). The main caracteristics of the GC-MS methods currently used are described. The problems posed by PBDE extraction from environnemental matrices and biological fluids are also approached.

Recent advances in collisional effects on spectra of molecular gases and their practical consequences

International audienceWe review progress, since publication of the book "Collisional effects on molecular spectra Laboratory experiments and models, consequences for applications" (Elsevier, Amsterdam, 2008), on measuring, modeling and predicting the influence of pressure (ie of intermolecular collisions) on the spectra of gas molecules. We first introduce recently developed experimental techniques of high accuracy and sensitivity. We then complement the aforementioned book by presenting the theoretical approaches, results and data proposed (mostly) in the last decade on the topics of isolated line shapes, line-broadening and-shifting, line-mixing, the far wings and associated continua, and collision-induced absorption. Examples of recently demonstrated consequences of the progress in the description of spectral shapes for some practical applications (metrology, probing of gas media, climate predictions) are then given. Remaining issues and directions for future research are finally discussed

High resolution Fourier transform spectroscopy of HD 16O: Line positions, absolute intensities and self broadening coefficients in the 8800-11,600cm -1 spectral region

High-resolution water vapor absorption spectra have been measured at room temperature in the 8800-11,600cm -1 spectral region. They were obtained using the mobile BRUKER IFS 120M Fourier transform spectrometer (FTS) from ULB-SCQP coupled to the 50m base long multiple reflection White type cell in GSMA laboratory. The absorption path was 600m and different H 2O/HDO/D 2O mixtures were used. Measurements of line positions, intensities and self-broadening coefficients were performed for the HD 16O isotopologue. 6464 rovibrational assignment of the observed lines was made on the basis of global variational predictions and allowed the identification of new energy levels. 3ν 3, 2ν 1+ν 3, 3ν 1+ν 2, ν 1+2ν 3 and 2ν 2+2ν 3 are the five strongest bands. The present paper provides a complementary data set on water vapor for atmospheric and astrophysical applications. © 2012 Elsevier Ltd.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

The 2015 edition of the GEISA spectroscopic database

The GEISA database (Gestion et Etude des Informations Spectroscopiques Atmosphériques: Management and Study of Atmospheric Spectroscopic Information) has been developed and maintained by the ARA/ABC(t) group at LMD since 1974. GEISA is constantly evolving, taking into account the best available spectroscopic data. This paper presents the 2015 release of GEISA (GEISA-2015), which updates the last edition of 2011 and celebrates the 40th anniversary of the database. Significant updates and additions have been implemented in the three following independent databases of GEISA. The “line parameters database” contains 52 molecular species (118 isotopologues) and transitions in the spectral range from 10−6 to 35,877.031 cm−1, representing 5,067,351 entries, against 3,794,297 in GEISA-2011. Among the previously existing molecules, 20 molecular species have been updated. A new molecule (SO3) has been added. HDO, isotopologue of H2O, is now identified as an independent molecular species. Seven new isotopologues have been added to the GEISA-2015 database. The “cross section sub-database” has been enriched by the addition of 43 new molecular species in its infrared part, 4 molecules (ethane, propane, acetone, acetonitrile) are also updated; they represent 3% of the update. A new section is added, in the near-infrared spectral region, involving 7 molecular species: CH3CN, CH3I, CH3O2, H2CO, HO2, HONO, NH3. The “microphysical and optical properties of atmospheric aerosols sub-database” has been updated for the first time since 2003. It contains more than 40 species originating from NCAR and 20 from the ARIA archive of Oxford University. As for the previous versions, this new release of GEISA and associated management software facilities are implemented and freely accessible on the AERIS/ESPRI atmospheric chemistry data center website.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

The HITRAN2020 molecular spectroscopic database

The HITRAN database is a compilation of molecular spectroscopic parameters. It was established in the early 1970s and is used by various computer codes to predict and simulate the transmission and emission of light in gaseous media (with an emphasis on terrestrial and planetary atmospheres). The HITRAN compilation is composed of five major components: the line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, experimental infrared absorption cross-sections (for molecules where it is not yet feasible for representation in a line-by-line form), collision-induced absorption data, aerosol indices of refraction, and general tables (including partition sums) that apply globally to the data. This paper describes the contents of the 2020 quadrennial edition of HITRAN. The HITRAN2020 edition takes advantage of recent experimental and theoretical data that were meticulously validated, in particular, against laboratory and atmospheric spectra. The new edition replaces the previous HITRAN edition of 2016 (including its updates during the intervening years).All five components of HITRAN have undergone major updates. In particular, the extent of the updates in the HITRAN2020 edition range from updating a few lines of specific molecules to complete replacements of the lists, and also the introduction of additional isotopologues and new (to HITRAN) molecules: SO, CH$_3$F, GeH$_4$, CS$_2$, CH$_3$I and NF. Many new vibrational bands were added, extending the spectral coverage and completeness of the line lists. Also, the accuracy of the parameters for major atmospheric absorbers has been increased substantially, often featuring sub-percent uncertainties. Broadening parameters associated with the ambient pressure of water vapor were introduced to HITRAN for the first time and are now available for several molecules.The HITRAN2020 edition continues to take advantage of the relational structure and efficient interface available at www.hitran.org and the HITRAN Application Programming Interface (HAPI). The functionality of both tools has been extended for the new edition