Development of liquid chromatography methods coupled to mass spectrometry for the analysis of substances with a wide variety of polarity in meconium.

International audienceMeconium is the first fecal excretion of newborns. This complex accumulative matrix allows assessing the exposure of the fetus to xenobiotics during the last 6 months of pregnancy. To determine the eventual effect of fetal exposure to micropollutants in this matrix, robust and sensitive analytical methods must be developed. This article describes the method development of liquid chromatography methods coupled to triple quadrupole mass spectrometry for relevant pollutants. The 28 selected target compounds had different physico-chemical properties from very polar (glyphosate) to non-polar molecules (pyrethroids). Tests were performed with three different types of columns: reversed phase, ion exchange and HILIC. As a unique method could not be determined for the simultaneous analysis of all compounds, three columns were selected and suitable chromatographic methods were optimized. Similar results were noticed for the separation of the target compounds dissolved in either meconium extract or solvent for reversed phase and ion exchange columns. However, for HILIC, the matrix had a significant influence on the peak shape and robustness of the method. Finally, the analytical methods were applied to “real” meconium samples

Development of a multi-residue method in a fetal matrix : analysis of meconium

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Determination of cis-permethrin, trans-permethrin and associated metabolites in rat blood and organs by gas chromatography–ion trap mass spectrometry

International audienceAn analytical method was developed to measure cis-permethrin and trans-permethrin in different biological rat matrices and fluids (whole blood, red blood cells, plasma, brain, liver, muscle, testes, kidneys, fat and faeces). The method was also suitable for the simultaneous quantification of their associated metabolites [cis-3-(2,2-dichlorovinyl)-2,2-dimethyl-(1-cyclopropane) carboxylic acid (cis-DCCA), trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-(1-cyclopropane) carboxylic acid (trans-DCCA) and 3-phenoxybenzoic acid (3-PBA)] in blood (whole blood, red blood cells, plasma) and liver. The target analytes were derivatised in samples using a methanolic/hydrochloric acid solution and then extracted with toluene. The analysis was performed by gas chromatography, and detection using ion trap tandem mass spectrometry. The selectivity obtained for complex matrices such as rat organs allowed the use of a purification step to be avoided for most of the matrices investigated. In the case of fat, where permethrin is suspected to accumulate, a dedicated purification step was developed. In fluids, the limits of quantification were at the 50 ng/mL level for the parent compounds and 3-PBA and at 25 ng/mL for cis-DCCA and trans-DCCA. For solid matrices excluding fat, the limits of quantification ranged from 50 ng/g for muscle to 100 ng/g for brain and testes for both cis-permethrin and trans-permethrin. The extraction recoveries ranged primarily between 80 and 120 % for the matrix tested. The stability of blood samples was tested through the addition of 1 % v/v formic acid. The methods developed were applied in a toxicokinetic study in adult rats. cis-Permethrin and the metabolites were detected in all corresponding matrices, whereas trans-permethrin was detected only in blood, plasma and faeces

Reliability of organic compounds measurement in enviromental monitoring. The key role of analytical standard substance. A study case on alkylphenols

The overall management and decision making system driven by the Water Framework Directive (WFD) and other European water policies is strongly dependent on the quality of monitoring data. Performing fit for purpose measurements implies the demonstration of their metrological traceability, their procuration according to accurate and sensitive analytical methods and a realistic estimate of expanded uncertainty. This can only be achieved by the provision of reference measurement standard substances, whenever possible traceable to the SI, which serve as reference points for the implementation of a traceability infrastructure supporting a monitoring network in Europe. Routine laboratories operating in French water bodies monitoring program have repeatedly expressed to AQUAREF their difficulties regarding alkyphenols, one of the priority substances of the WFD. Accordingly, LNE and INERIS handled a study that aims at assessing the purity of nonylphenols commercially available analytical standard and discusses its impacts. The work highlights that: identity of the organic analytical standard substance reference materials should be clearly documented and demonstrated, purity assessment should be reported with a reliable uncertainty evaluation

Development of liquid chromatography methods coupled to mass spectrometry for the analysis of substances with a wide variety of polarity in meconium

Meconium is the first fecal excretion of newborns. This complex accumulative matrix allows assessing the exposure of the fetus to xenobiotics during the last 6 months of pregnancy. To determine the eventual effect of fetal exposure to micropollutants in this matrix, robust and sensitive analytical methods must be developed. This article describes the method development of liquid chromatography methods coupled to triple quadrupole mass spectrometry for relevant pollutants. The 28 selected target compounds had different physico-chemical properties from very polar (glyphosate) to non-polar molecules (pyrethroids). Tests were performed with three different types of columns: reversed phase, ion exchange and HILIC. As a unique method could not be determined for the simultaneous analysis of all compounds, three columns were selected and suitable chromatographic methods were optimized. Similar results were noticed for the separation of the target compounds dissolved in either meconium extract or solvent for reversed phase and ion exchange columns. However, for HILIC, the matrix had a significant influence on the peak shape and robustness of the method. Finally, the analytical methods were applied to "real" meconium samples.publisher: Elsevier articletitle: Development of liquid chromatography methods coupled to mass spectrometry for the analysis of substances with a wide variety of polarity in meconium journaltitle: Talanta articlelink: http://dx.doi.org/10.1016/j.talanta.2015.02.058 content_type: article copyright: Copyright © 2015 Elsevier B.V. All rights reserved.status: publishe

Aerosolomics based approach to discover source molecular markers: A case study for discriminating residential wood heating vs garden green waste burning emission sources

International audienceBiomass burning is a significant source of particulate matter (PM) in ambient air and its accurate source apportionment is a major concern for air quality. The discrimination between residential wood heating (RWH) and garden green waste burning (GWB) particulate matter (PM) is rarely achieved. The objective of this work was to evaluate the potential of non-targeted screening (NTS) analyses using HRMS (high resolution mass spectrometry) data to reveal discriminating potential molecular markers of both sources. Two residential wood combustion appliances (wood log stove and fireplace) were tested under different output conditions and wood moisture content. GWB experiments were carried out using two burning materials (fallen leaves and hedge trimming). PM samples were characterized using NTS approaches with both LC- and GC-HRMS (liquid and gas chromatography-HRMS). The analytical procedures were optimized to detect as many species as possible. Chemical fingerprints obtained were compared combining several multivariate statistical analyses (PCA, HCAand PLS-DA). Results showed a strong impact of the fuel nature and the combustion quality on the chemical fingerprints. 31 and 4 possible markers were discovered as characteristic of GWB and RWH, respectively. Complementary work was attempted to identify potential molecular formulas of the different potential marker candidates. The combination of HRMS NTS chemical characterization with multivariate statistical analyses shows promise for uncovering organic aerosol fingerprinting and discovering potential PM source markers

Realistic assessment of the effects of bisphenol A on a fish population in ecosystemic conditions

There is a clear lack of information on the impact of bisphenol A (BPA) on ecologically relevant endpoints, at both population and community scale. The pattern of effects is complex and ranges from behavioral disorder to reproductive impairments, therefore the resulting effects on a population can only properly be assessed through long term exposure in an ecosystemic context. Mesocosms studies provide such information for small fish like Gasterosteus aculeatus, a known suitable fish species to study endocrine disruption. INERIS mesocosms are designed for long term study of communities, in an ecosystemic context characterized by spatial heterogeneity, species heterogeneity and density-dependent effects. The mesocosms were set up in November with the selected nonfish species, introduced in quantities and at locations defined in a uniform protocol for each treatment. In the beginning of March, initial tagged populations were introduced in each mesocosm. 15 females and 10 males per mesocosm were selected. Based on literature data, three nominal concentrations of BPA were selected: 1, 10 and 100 µg/L. Treatment began in mid-April and ended by the end of September. Five groups of fish were identified: juvenile (< 25 mm), non-founder fish (? 25 mm without tag) male or female, founder fish male or female (? 25 mm with tag). The populations were compared based on the abundance of these different groups of fish, on the sex-ratio, on the condition index, and on the length frequency distribution of the fish population. The value of pH was significantly lower in 100 µg/L of BPA than in the other treatments. This observation could be explained by the more important number of invertebrates such as gastropods and/or the lower biomass of macrophyte. Concentrations of BPA measured were close to the nominal concentrations at 0 m from the inlet of the water in mesocosm then, concentrations decreased and were stable 5m after the inlet. Populations exposed to 100 µg/L of BPA showed a number of non-founder females and males and a juvenile length significantly higher than in the other populations. In our study, BPA perturbed the structure of the population at the maximum exposure concentration. Other trophic levels observed during the same experiments are being analysed to complete these results. We believe that the outcomes of the whole study would be a right basis for ecologically relevant risk assessment of bisphenol A

Preliminary interlaboratory trial for ISO/DIS 12010 : determination of short chain polychlorinated alkanes (SCCP) in water

International audienceA first preliminary interlaboratory trial was planned to prepare ISO/DIS 12010: Water quality - determination of short chain polychlorinated alkanes (SCCP) in water - method using GC/MS and electron capture negative ionisation (ECNI). The task was to determine the sum of short chain polychlorinated n-alkanes with carbon chain lengths of C10-C13 and a chlorine content between 49 and 67% in water by GC-ECNI-MS and quantification by multiple linear regression described in ISO/DIS 12010 as the compulsory method. Distributed samples were obtained from a real water extract spiked with a target concentration of 0.4 micro g/mL sum of SCCP, i.e. the environmental quality target level according to the Water Framework Directive. The interlaboratory trial included the calibration, a column chromatographic clean up, a concentration step and an integration of chromatographic unresolved humps as well as the quantification with multiple linear regression. Reproducibility standard deviations between 21.5 and 22.9% were achieved by 17 participating laboratories from four countries. The method outlined no significant difference of the results between the standard solution and a real water matrix extract. On the basis of this succeeded preliminary interlaboratory trial the final interlaboratory trial for validation of ISO 12010 was prepared in autumn 2010

Effects of bisphenol A on different trophic levels in a lotic experimental ecosystem

International audienceBisphenol A (BPA) is commonly used by manufacturers and can be found in many aquatic ecosystems. Data relative to BPA ecotoxicity are only available for studies in laboratory conditions on macro-invertebrates and fish. There is thus a lack of information for other trophic levels such as macrophytes. Moreover, the impacts of BPA within an ecosystem context, i.e. with populations from different trophic levels studied at long term in environmental conditions, have never been assessed. We carried out a long-term lotic mesocosm study in 20 m long channels under three exposure concentrations of BPA (nominal concentrations of 0, 1, 10 and 100 mu g/L) delivered continuously for 165 days. Three trophic levels were followed: macrophytes, macro-invertebrates (with a focus on Radix balthica) and fish (Gasterosteus aculeatus). Significant effects were shown at 100 mu g/L BPA on the three trophic levels. BPA had a direct impact on macrophyte community structure, direct and indirect impacts on macro-invertebrates and on fish population structure. Gonad morphology of fish was affected at 1 and 10 mu g/L of BPA, respectively for female and male sticklebacks. In addition to these ecotoxicity data, our results suggest that fish are good integrators of the responses of other communities (including macro-invertebrates and macrophytes) in mesocosm systems

Bio-analytical assessment of primary vs. aged biomass burning emissions

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