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

Non-target screening and environmental specimen banking: French perspectives

International audienceIn 2016, French regulatory bodies launched a new and ambitious monitoring program so called “prospective monitoring network”, in view of improving and promoting knowledge acquired about the occurrence of contaminants in water environments. Among various actions supported by this program, a specific one is focused on non-target screening strategies. It aims, in particular to demonstrate and highlight the potential of suspect- and non-target screening approaches for retrospective analysis in connection with environmental specimen banking (either physical samples or digital data). In fact, some mass spectral data banks have been recently built at the level of the research community but outside from conventional ESBs arena and without complete raw data storage, which reduce potential data reprocessing. Among its major advantages: retrospective analysis and elucidation of unknown compounds; alternatives to specimen banking of conventional matrix can be highlighted. As instance, a prototype of a 'Digital Sample Freezing Platform' has been developed by the NORMAN network, to host full scan liquid chromatography-mass spectrometry data, allowing for retrospective analysis of any environmental sample for a wide range of pollutants. In this context the action of AQUAREF aims to address the following points, essential for improved design of ESBs for NTS applications and to ensure the exploitability of such ESB:•Appropriate codification to allow an efficient data exchange •Key metadata that have to be stored and made available •Properties of samples and data, accessibility, promotion•Metrological infrastructure: long term storage, QA/QC, SOP, …The proposal will present French works that are currently performed by AQUAREF consortium (French Reference Laboratory for Water and Aquatic Environment)

A French collaborative study to evaluate the impact of acquisition workflow with LC-HRMS on environmental data

International audienceAQUAREF, the French national reference laboratory of aquatic environment monitoring, is a consortium of five French national research institutes (BRGM, IFREMER, INERIS, Irstea and LNE) joined together to reinforce the French expertise in aquatic environments monitoring. AQUAREF aims at developing and testing the operational applicability of new tools and innovative strategies for the identification of emergent contaminants in a more relevant and cost-effective way. High resolution mass spectrometry coupled with chromatography already presents great interest for non-targeted and suspected screening approaches. However, in order to integrate these new methodologies for the aquatic environment monitoring, the different laboratory practices should be well identified and harmonized. In that way a collaborative trial was made with 11 French laboratories using LC-HRMS with several different equipments.The aim of this intercomparison exercise was to identify the impact of chromatographic methods (shift of retention time,ionization, …), specificity of equipment (detection, fragmentation, …) and source of databases (intern obtained from standard injections or extern by the use of bibliographic, constructor or on-line databases) on identification of compounds.Two test materials were sent to the laboratories: a solution spiked with standards and a river SPE extract (unspiked). In addition, both material tests were analysed with a unique analytical method imposed by AQUAREF and with the laboratories own methods in positive and negative electrospray ionisation modes.Raw analytical data were firstly processed (both standard mix solution and river SPE extract) with a targeted or suspected screening approaches (levels of confidence 1 or 2 from the classification of Schymanski - (Schymanski et al., 2014) based on a list of 30 compounds and target database of each laboratories. Then, the river SPE extract was treated for suspect compound identification based on a common database of 16 compounds.For the targeted and suspected screening approaches, the results highlighted that:•The most relevant compounds were identified in river SPE extract by all expert laboratories. More than 100 compounds were determined between all laboratories.•For compounds identification, the mastering level is better in the positive electrospray ionization mode than the negative one;•A generic chromatographic method can cover a wide range of molecules but from the standard mix analysis, exclusions could be observed•there is a need of homogenization surrounding qualification of data compliance (validation criteria) in addition to the implementation of Schymanski classification •Need to implement QA/QC validation steps (blank, internal standards, …)•This exercise has been helpful because it has served to share common difficulties (not distinguishable isomers, sample contaminations…) between expert laboratories. Concerning communication to the end users, there is a need to clarify the expression of results, by being clear about limitations (data compliance, false negative/positive, etc…)

A simple QuEChERS-like extraction approach for molecular chemical characterization of organic aerosols: application to nitrated and oxygenated PAH derivatives (NPAH and OPAH) quantified by GC–NICIMS

International audienceAn extraction procedure based on the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) approach has been developed and used for analysis of particle-bound nitrated and oxygenated PAH derivatives (NPAH and OPAH, respectively). Several analytical conditions, for example GC injection temperature and MS detection settings, were optimized. This analytical procedure enabled simultaneous GC–NICIMS quantification of 32 NPAH and 32 OPAH (or other oxygenated compounds), including typical components of secondary organic aerosol (SOA) formed by photooxidation of PAH (e.g. 2-formyl-trans-cinnamaldehyde and 6H-dibenzo[b,d]pyran-6-one). The QuEChERS-like approach was optimized, including the nature of the extraction solvent, the sorbent used for clean-up, and extraction time. The final extraction procedure was based on brief mechanical agitation (vortex mixing for 1.5 min), with 7 mL acetonitrile as solvent. Because dispersive solid-phase extraction (d-SPE) did not provide satisfactory results, SPE using SiO2 was selected for sample purification. Identical results were obtained when the QuEChERS-like and traditional pressurised solvent extraction (PLE) procedures were compared for analysis of fortified ambient air particle samples. The procedure was validated by analysis of two aerosol standard reference materials (NIST SRM 1649b (urban dust) and SRM 2787 (fine particulate matter, <10 µm)). For numerous NPAH and OPAH, this is the first report of their quantification in both SRMs. Compared with other extraction methods, including PLE, the QuEChERS-like procedure resulted in increased productivity and reduced extraction cost. This paper shows that QuEChERS-like extraction procedures can be suitably adapted for molecular chemical characterization of aerosol samples and could be extended to other categories of compound

Per- and Polyfluoroalkyl Substances (PFAS) in Surface Sediments: Occurrence, Patterns, Non-Physical Drivers and Contribution of Unidentified Precursors in French Aquatic Environments

International audienceSediment acts as a sink for per- and polyfluoroalkyl substances (PFAS), especially for perfluoroalkyl sulfonic acids (PFSAs) and perfluoroalkyl carboxylic acids (PFCAs). Recently, non-targeted methods have shown the presence of numerous unknown PFAS in environmental samples. The contribution of these PFAS can be estimated by the Total Oxidisable Precursor assay (TOP), an oxidative method used to convert polyfluoroalkyl precursors (pre-PFAAs) into perfluoroalkyl acids (PFAAs). While sediment properties (grain size and organic carbon fraction, foc) were reported as controlling factors for some PFAS, the influence of non-physico-chemical drivers (e.g. population density) still needs to be investigated. Thus, this work focused on sediments from France and used optimized analytical methods and geographical information system (GIS) to fill these knowledge gaps. Extraction solvent was modified from methanol (MeOH) + ammonium hydroxide to MeOH + ammonium acetate for the analysis of 16 PFAAs, 6 alternative PFAAs and 14 pre-PFAAs covering anionic, neutral and zwitterionic species (n:2 fluorotelomer sulfonamidoalkyl betaines, n:2 FTABs). The optimized method exhibited suitable performances for its application on sediments (n=50) collected in 2018. The TOP assay was adapted to this specific method extraction. Perfluorododecanic acid,perfluorooctane sulfonic acid (PFOS) as well as perfluorooctanoic acid (PFOA) were often detected (76, 74 and 68 % respectively). 6:2 FTAB, 8:2 FTAB and perfluoropentyl propanoic acid (FPePA) were also detected (38, 26 and 36 %, respectively). Median ∑PFAS was 1.3 ng.g-1 dry weight (dw) (range < LOD–23 ng.g-1 dw). 6:2 FTAB and 8:2 FTAB levels ranged from < 0.36 to 6.4 ng.g-1 dw and < 0.50 to 7.4 ng.g-1 dw, which is in the same order of magnitude than L-PFOS (< 0.08–5.1 ng.g-1 dw) advocating for the necessity to include these PFAS in targeted analysis. At nationwide scale, PFOS and ∑PFCAs accounted for 37 ± 25% and 31 ± 21% of ∑PFAS, respectively, while targeted pre-PFAAs accounted for 29 ± 27%, thereby supporting the importance of the latter in sediment and the potential contribution of untargeted pre-PFAAs monitored by the TOP assay (data under acquisition). Correlations between PFAS levels normalized by foc, unidentified pre-PFAAs and non-physico-chemical drivers with GIS are being investigated. Preliminary results showed that PFAS levels were not correlated with sample site position in the hydrographic system (proxy: Strahler number)

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

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

Analysis of BTEX and chlorinated solvents in meconium by headspace-solid-phase microextraction gas chromatography coupled with mass spectrometry.

International audienceMeconium is the earliest stool of newborns, and is a complex matrix that reflects the degree of exposure of the fetus to xenobiotics. To investigate fetal exposure to volatile organic compounds, an analytical method was developed to identify and quantify BTEX (benzene, toluene, ethylbenzene, and o,m,p-xylene) and two chlorinated solvents (trichloroethylene and tetrachloroethylene) in meconium. Headspace-solid-phase microextraction coupled with gas chromatography-mass spectrometry was selected because it is simple, sensitive, can be automated, and requires no extensive sample preparation. Several extraction variables were optimized (fiber type, incubation time, temperature of fiber, and use of salt). Because meconium is a complex matrix, quantification by SPME was considered carefully because of potential interference, for example competitive adsorption. Calibration in water was compared with calibration in meconium using external and internal methods (with isotope-labeled compounds). In meconium, limits of quantification were determined to be in the range 0.064-0.096 ng g(-1) for the investigated compounds. All target compounds were determined in "real-case" meconium samples

Development and Implementation of Automated Qualification Processes for the Identification of Pollutants in an Aquatic Environment from High-Resolution Mass Spectrometric Nontarget Screening Data

International audienceEnvironmental pollution monitoring represents a major challenge due to the growing presence of a large and diverse number of potential contaminants. In complement to target analysis, nontarget analysis, via liquid chromatography (LC) coupled to high-resolution mass spectrometry (HRMS), is increasingly used to provide a more comprehensive characterization of pollution. The challenge associated with this type of analysis is particularly related to the data treatment for substance identification. One of the main limitations is that all data must be manually reviewed, which is tedious and time-consuming. Machine learning algorithms aim to reproduce human behavior, and their capabilities were therefore evaluated to automatically identify substances in suspect screening approaches. After selecting the relevant features produced from LC/HRMS, seven different machine learning models were evaluated for each of the three different databases, which resulted in the selection of logistic regression (LR) and random forest (RF)-based algorithms. An interface was built to rank the identified substances and to assess the performance of the developed models. The LR model provided the best results when retention times were available. The developed LR and RF models were determined complementarily, particularly when no retention times were available. However, limitations were noticed when using a database containing different HRMS technologies

Monitoring priority substances in biota under the Water Framework Directive: how effective is a tiered approach based on caged invertebrates? A proof-of-concept study targeting PFOS in French rivers

International audienceBackground This study aims to describe and test a tiered approach for assessing compliance to Environmental Quality standards (EQSs) for priority substances in biota in line with the European Water Framework Directive. This approach is based on caged gammarids and trophic magnification factors (TMFs) at the first tier, with fish analyzed at the second tier at sites predicted to exceed the EQS at the first tier. A dataset was implemented by monitoring perfluorooctane sulfonate (PFOS) in caged gammarids exposed at 15 sites in French rivers, and in fish muscle and rest-of-body from the same sites. Isotopic ratios (delta C-13 and delta(15) N) were also measured in gammarids and fish. Two scenarios were developed to compare measured PFOS concentrations in fish against predicted concentrations based on measures in caged gammarids and TMFs. Scenario (1) compared measured PFOS concentrations in fish fillets with predicted PFOS concentrations based on measured concentrations in caged gammarids and delta(15) N. Scenario (2) tested whether or not EQS exceedance was correctly predicted based on measured concentrations in caged gammarids and trophic levels (TLs) from wild fish and gammarid populations. Results delta C-13 and delta(15) N variations showed that caged gammarids used local food resources during exposure in the field. PFOS concentrations in gammarids were fairly variable through time at each site. In fish, concentrations ranged from < 1 to 250 ng g(-1)(wet weight). After adjustment to the TL at which the EQS is set, 12 sites were above the EQS for PFOS. In scenario (1), predicted concentrations were almost correct at 7 sites out of 15. Most incorrect predictions were overestimations that were slightly improved by applying a lower (neutral) TMF. In scenario (2) we tested several variants for parameters involved in the predictions. The most efficient combination yielded two wrong predictions out of 15. This result was obtained with a higher (more conservative) TMF value, mean concentrations in gammarids from several field exposures during a year, and a TL for gammarids at the median of the distribution in French rivers. Conclusion The proposed tiered approach was thus efficient. However, the number of sites was relatively limited, and the dataset was biased towards EQS exceedance. The tiered approach warrants further validation