Development of air and dust sampling methods for quantitative measurements of polybromated diphenyl ethers (PBDEs) in offices

International audienc

A really quick easy cheap effective rugged and safe (QuEChERS) extraction procedure for the analysis of particle-bound PAHs in ambient air and emission samples

International audienceA quick easy cheap effective rugged and safe (QuEChERS) like extraction procedure is presented for the measurement of polycyclic aromatic hydrocarbons (PAHs) associated to particulate matter from ambient air or combustion process. The procedure is based on a short mechanical agitation (vortex during 90 s) using a small volume of acetonitrile (7 ml) as extraction solvent. Equivalent extraction efficiencies were obtained when comparing the QuEChERS and the traditional pressurized solvent extraction (ASE) procedures for ambient air and emission (wood combustion) filter samples. The developed QuEChERS extraction protocol was validated with the analysis of a standard reference material (NIST SRM 1649a, urban dust). By comparison to other extraction methods including ASE, the simplicity of the QuEChERS protocol allows to minimize experimental errors, to decrease about a factor 5 the cost per extraction and to increase the productivity per working day by a 10-fold factor. This paper constitutes the first report on the applicability of a QuEChERS-like approach for the quantification of PAHs or other organic compounds in atmospheric particulate matter

Evaluation of QuEChERS approach for the analysis of polycyclic aromatic hydrocarbons in sediments

Polycyclic aromatic hydrocarbons (PAHs) are mainly produced as by-products from the incomplete combustion of organic matter and fossil fuel. They constitute ubiquitous environmental contaminants and are of main concern since their toxicities have been widely demonstrated (carcinogenic and/or mutagenic properties notably). Regarding aquatic environment, they have been included in the list of priority substances as defined by the European Union Water Framework Directive. Their monitoring is therefore mandatory to assess the quality of aquatic media. The PAH are hydrophobic component so are mostly adsorbed onto sediments. Extraction using pressurized fluid is the most popular method for sediment sample treatment. It is very efficient for extracting the target analytes but also all the other potentially interfering components that might be present within the matrix. Moreover, this technique is relatively expensive since dedicated equipment is needed. The QuEChERS approach, developed initially for the analysis of pesticides in fruits and vegetables, can be regarded as an alternative technique to simplify this step. It is easy to handle, relatively cheap and with low solvent consumption. Therefore, this technique has been evaluated in this study for the extraction and sample treatment of PAH in sediments. The analysis of PAH was then performed by gas chromatography coupled to mass spectrometry. A QuEChERS type method and purification protocol based on the approach generally carried out for fruits and vegetables was applied. An extraction with vortex agitation using acetonitrile was performed followed by a purification step by dispersive solid phase extraction. Extraction parameters such as agitation time were investigated. Influence of water addition to sediments was determined as a particularly significant parameter on recoveries of PAH. The purification step was also evaluated with the test of several phases. Finally, the optimized protocol was tested on several sediments and on reference certified materials. Overall, in most cases, the QuEChERS based approach appeared suitable for the analysis of PAH in sediments

Application of QuEChERS based methodology for the analysis of pesticides in sediments

The analysis of micropollutants present in sediments generally requires to carry out a complex protocol including several successive steps for sample extraction and purification. The most popular method, the extraction by pressurised fluid, is very efficient for extracting the target analytes but also for all the other potentially interfering components that might be present within the matrix. Moreover, this technique is relatively expensive since dedicated equipment is needed. The QuEChERS approach, developed initially for the analysis of pesticides in fruits and vegetables, can be regarded as an alternative technique to simplify this step. It is easy to handle, relatively cheap and with low solvent consumption. Therefore, this technique has been evaluated in this study for the analysis of pesticides in sediments. The priority pesticides and the substances candidate to integrate the Water Framework Directive (2000/60/EC) list of pollutants were considered. Since the purification step of the QuEChERS technique is not intended to remove all interferents from the sample matrix, the analysis was performed by gas chromatography followed by a selective detection using tandem mass spectrometry. A QuEChERS type method and purification protocol based on the approach generally carried out for fruits and vegetables was applied. Therefore, an extraction with vortex agitation using acetonitrile was performed followed by a purification step by dispersive solid phase extraction with sodium sulfate, C18 or PSA. Initial tests were carried out on dry sediments but addition of 10 to 20% of water (v/w) increased the recovery of most of the pesticides tested. With this approach, recoveries ranging from 80 to 120 % were obtained for most of tested compounds. Limit of quantification were determined around 10 ng/g with linearity range up to 500 ng/g. This protocol was tested on certified reference material which provided satisfying results in most cases. Overall, the QuEChERS based approach appeared suitable for the analysis of pesticides in sediments

Molecular chemical characterization of organic aerosols using QuEChERS-like extraction approach : application to PAHs and their nitrated and oxygenated derivatives (NPAHs and OPAHs)

Alternative extraction procedures based on a QuEChERS approach (Quick Easy Cheap Effective Rugged and Safe) were developed for the measurement of PAHs and PAH derivatives (nitrated and oxygenated PAHs) associated to particulate matter from ambient air or combustion processes. The procedures are based on a short mechanical agitation (vortex) using a small volume of solvent (< 10 ml) and including, if necessary, a purification step by solid phase extraction (SPE) or dispersive-SPE (d-SPE). Different extraction parameters were optimized such as agitation time, solvent nature, adsorbent for clean-up. Equivalent extraction efficiencies were obtained when comparing the QuEChERS-like and the commonly used pressurized solvent extraction procedures (PLE) for ambient air and emission (wood combustion) filter samples

Analytical method of volatile aromatic compounds in water and meconium by HSSPME/GC/MS: influence of matrix

Meconium is the earliest stools of newborn. It starts forming from the 13th week of gestation in intestinal contents and accumulates until birth. Usually, it is expelled by the newborn between 24 and 48 hours after birth. This complex matrix has the advantage to integrate a large period of exposure of the foetus to xenobiotics while urine and blood only represent a short-term exposure. This work presents analytical consideration for the detection and the quantification of volatile aromatic compounds (VOCs): BTEX (benzene, toluene, ethylbenzene and xylene) and chlorinated solvents (trichloroethylene and tetrachloroethylene) in meconium. This biological matrix is very viscous and sticky, very difficult to manipulate and homogenize. To analyze VOCs, a headspace analysis method avoiding laborious sample preparation due to the complexity of meconium was selected. Analyzes were then carried out by HeadSpace Solid Phase MicroExtraction (HSSPME) coupled with Gas Chromatography coupled to Mass Spectrometry (GC/MS). As meconium is a rare and heterogeneous matrix from one infant to the others, matrix calibration is difficult to perform. This work has investigated if calibration in water could be used for quantification of target components. The addition of isotopic labelled internal standard for each of the target compounds has allowed a correction of these differences when ratio of standard on internal standard is applied. External and internal calibrations were compared in these two matrices. It was particularly studied if the correction with isotopic labelled internal standards is adequate to use an internal calibration in water to quantify molecules in meconium (it contains 70% of water). Influence of the matrix was observed on the response obtained with a significant decrease in amount of molecule, adsorbed on the fibre, when comparing sampling using meconium and water. The results have shown that the quantification by external calibration is less reliable than the internal calibration in these matrices. It also appears that the correction with isotopic labelled internal standards is not enough to allow the transposition of internal calibration in water to quantification in meconium for all target compounds. Analyzes of meconium were carried out with an internal calibration in meconium for BTEX and chlorinated solvents. The limit of quantification was 80 pg/g for most of the compounds

Chemical characterization of SOA from diesel and gasoline vehicles with untargeted approaches

Recent studies have shown that the PM emissions of modern cars equipped with the newest after-treatment technologies are mainly related to the production of secondary organic aerosols (SOA) especially in the case of gasoline vehicles. The objective of this work is to identify specific molecular markers or chemical patterns that can be further used in PM source apportionment studies to discriminate SOA from diesel and gasoline vehicles. Experiments were performed on a chassis dynamometer with a gasoline and diesel Euro 5 vehicles. Exhaust emissions were diluted before introduction into a potential aerosol mass (PAM) oxidation flow reactor (OFR) for aging and SOA formation. About 50 filter samples were collected upstream and downstream the PAM-OFR and analyzed using innovative non-targeted approaches with high-resolution mass spectrometry coupled to gas or liquid chromatography. The data treatment and statistical analysis will allow to highlight features or chemical patterns specific of gasoline and diesel SOA

Développement de deux méthodes pour l'analyse de composés organiques volatils, de pesticides et des métabolites associés dans le méconium

Le méconium est une matrice complexe analysée afin de déterminer si le degré d'exposition des foetus aux xénobiotiques joue un rôle dans la survenue de malformations, ceci dans le cadre du projet PHRC " PENEW " (Pregnancy Environment and NEWborn malformations, PHRC 2010, CHU Rennes). Le développement analytique pour la détection et le dosage dans le méconium de BTEX (benzène, toluène, éthylbenzène, xylènes), de deux solvants trichlorés (trichloroéthylène et tétrachloroéthylène) issus de la famille des COVs (Composés Organiques Volatils), de pesticides (pyréthrinoïdes, organophosphorés...) et des métabolites associés est présenté dans ce travail. La préparation d'échantillon est complexe en raison des propriétés physico-chimiques très particulières du méconium. Concernant les COVs, la technique par MicroExtraction par Phase Solide (MEPS) en espace de tête couplée à une CG/SM a été choisie car elle ne nécessite pas de préparation préalable de l'échantillon et permet de le préserver pour une autre analyse (utile lors de faibles quantités collectées). L'analyse des métabolites de COVs, des pesticides et des métabolites de pesticides est ainsi réalisée sur le même échantillon par une extraction sur phase solide (SPE). Des cartouches de phases adsorbantes diverses (phase inverse, échange d'anions, échange de cations...) ont été évaluées. Les conditions de séparation des composés cibles ont été optimisées par le test de cinq colonnes d'interactions différentes (phase inverse, HILIC, mode mixte), par la variation des tampons aqueux pour l'analyse CL/SM/SM (nature et quantité du sel, pH) et par l'optimisation du gradient chromatographique. La colonne Rtx-WAX (30 m × 0.25 mm I.D., épaisseur de film de 0.50 µm) utilisée permet une séparation de tous les COVs étudiés en particulier les isomères du xylène. L'optimisation de la méthode par MEPS/CG/SM a montré que la fibre CAR/PDMS 85 µm produisait les meilleures sensibilités et que l'ajout de sel n'était pas nécessaire. Les paramètres d'extraction ont été choisis en considérant le meilleur compromis entre la sensibilité spectrométrique et le temps d'analyse. Les essais ont démontré qu'une calibration interne dans le méconium avec des étalons internes spécifiques de type isotopique pour chaque composé analysé était indispensable pour une quantification fiable dans cette matrice. Des limites de quantification (LQ) de l'ordre de 100 pg/g de méconium sont atteintes par cette méthode. Pour l'analyse par SPE/CL/SM/SM, les phases présentant les meilleurs rendements sont celles de type phase inverse (C18 polymérique) et échange d'anions forts (SAX). L'utilisation de trois colonnes d'interactions différentes pour la quantification est nécessaire pour l'analyse de ces molécules aux propriétés physico-chimiques très différentes : la RP-Amide (phase inverse) pour l'analyse des molécules apolaires et moyennement polaires ; la HILIC (phase normale) pour les molécules polaires et très polaires ; et la Trinity P1 (mode mixte) pour le glyphosate. L'optimisation des conditions chromatographiques permet l'utilisation des mêmes solvants pour ces trois colonnes. Des LQ de l'ordre de 10 ng/g de méconium sont obtenues avec cette méthode. Grâce à ces deux méthodes analytiques, basées sur l'utilisation du même échantillon contenant une faible quantité de méconium (1,25 g), il est possible de quantifier la quarantaine de molécules cibles et de mettre ainsi en évidence une exposition du foetus aux contaminants de l'environnement