Filtern
Erscheinungsjahr
Dokumenttyp
- Zeitschriftenartikel (87) (entfernen)
Schlagworte
- Interlaboratory comparison (9)
- Gas chromatography (6)
- Extraction (5)
- Analysis (4)
- Boden (4)
- Brominated flame retardant (4)
- Groundwater (4)
- HPLC-MS/MS (4)
- Breath (3)
- Chiral separation (3)
- Mass spectrometry (3)
- Microplastics (3)
- Proficiency testing (3)
- Ringversuch (3)
- VOC (3)
- Volatile organic compounds (3)
- Volatilome (3)
- A549 (2)
- Alcohol marker (2)
- Aniline (2)
- Certification (2)
- Certified reference materials (2)
- Chloroanilines (2)
- Crystal structure (2)
- Degradation (2)
- Diastereomers (2)
- Ethyl glucuronide (2)
- Flame retardant (2)
- Food (2)
- Fortification (2)
- GC-FID (2)
- GC-MS (2)
- HBCD (2)
- Hydroxylation (2)
- Kinetics (2)
- Liquid chromatography (2)
- Long term stability (2)
- Lung cancer (2)
- Methylanilines (2)
- Micropulverization (2)
- Mikroplastik (2)
- Molecular dynamics (2)
- Organic pollutants (2)
- Phenols (2)
- Reference materials (2)
- Sampling (2)
- Sewage sludge (2)
- Soil (2)
- Solid phase microextraction (2)
- Summation parameter (2)
- AOX (1)
- APCI (1)
- Abfall (1)
- Absolute configuration (1)
- Abwasser (1)
- Acrylamid (1)
- Active sampling (1)
- Adsorption (1)
- Akkreditierung (1)
- Analysis and identification (1)
- Analytik (1)
- Anomalous dispersion (1)
- Anomeric configuration (1)
- Antioxidant properties (1)
- Arrhenius model (1)
- Artificial weathering (1)
- BFR (1)
- BPA (1)
- BTEX (1)
- Bacteria (1)
- Benzenes (1)
- Beta-cyclodextrin (1)
- Binding affinity (1)
- Bio test battery (1)
- Bioaccumulation (1)
- Biochar (1)
- Biofouling (1)
- Bioisomerization (1)
- Biomarkers (1)
- Bleaching (1)
- Bromierte Falmmschutzmittel (1)
- Brominated flame retardants (1)
- CEC-L-103 (1)
- CRM (1)
- Calibration (1)
- Calix[4]resorcinarenes (1)
- Cancer (1)
- Chemical analysis (1)
- Chemometrics (1)
- Collaborative trial (1)
- Combustion (1)
- Conformational chirality (1)
- Contaminated site (1)
- Contamination (1)
- Crosslinking (1)
- Crystal structures (1)
- Cysteic acid (1)
- Cytochrom (1)
- Cytochrome P450 (1)
- Cytochromes (1)
- D-Glucuronic acid derivates (1)
- DEHP (1)
- DFA (1)
- Data-to-parameter ratio = 20.4 (1)
- Degradation of refrigerants (1)
- Derivatisation (1)
- Derivatisierung (1)
- Derivatization (1)
- Detection dog (1)
- Diffusionsprobe (1)
- Dithiocarbamate (1)
- Dithiopercarbamate (1)
- ERM (1)
- Einfluß (1)
- Eingnugsprüfung (1)
- Elution order (1)
- Enantiomer fraction (1)
- Enantiomer-specific bioaccumulation (1)
- Enantiomer-specific determination (1)
- Enantiomeric fraction (1)
- Enantiomers (1)
- Equivalence (1)
- Equivalent carbon number (1)
- European Reference Material (1)
- European reference material (1)
- European waste list (1)
- External quality management (1)
- FTIR imaging (1)
- Fish feeding experiment (1)
- Flame ionization detection (1)
- Flame retardants (1)
- Fluoroacetic acid (1)
- Fuel (1)
- Fungi (1)
- Furfurals (1)
- GC (1)
- GC-AED (1)
- GC/MS (1)
- GC/MS-MS (1)
- GCMS (1)
- Gaschromatographie (1)
- Gasoline (1)
- Ground water (1)
- Groundwater monitoring (1)
- Grundwasser (1)
- HBCDs (1)
- HPLC (1)
- HPLC-DAD (1)
- HPLC-ESI-MS/MS (1)
- HPLCMS/MS (1)
- Hair (1)
- Hair testing (1)
- Hexabromcyclododecan (1)
- High resolution NMR (1)
- High-throughput analysis (1)
- Homogeneity (1)
- Honey bees (1)
- Hydrocarbons (1)
- Hydrochar (1)
- Hydrogen bonded molecular capsule (1)
- ICP-MS (1)
- ICP-OES (1)
- IR spectrometry (1)
- Indoor air (1)
- Intercomparison (1)
- Interlaboratory study (1)
- International intercomparison (1)
- Ion chromatography (1)
- Isoleucin (1)
- Isomerisation (1)
- Kalibrierstand (1)
- Kompetenzbewertung (1)
- LC-MS (1)
- LC/MS-MS (1)
- LHKW (1)
- Lung cancer cell culture (1)
- MKW (1)
- MOSH/MOAH (1)
- Marker (1)
- Markov process (1)
- Measurement uncertainty (1)
- Metabolism of HBCD (1)
- Metaboliten (1)
- Metal-organic complexes (1)
- Methane (1)
- Method development (1)
- Method validation (1)
- Metrology (1)
- Micropulverized extraction (1)
- Mineral oil (1)
- Mineral oil hydrocarobons (1)
- Mineralölkohlenwasserstoff (1)
- Mineralölkohlenwasserstoffe (1)
- Minor isomers (1)
- Moisture (1)
- Molecular simulation (1)
- Municipal sludge (1)
- NPE (1)
- Nation metrology institutes (1)
- Near Infrared Spectroscopy (1)
- Network (1)
- Odour discrimination task (1)
- Optical rotation (1)
- Organohalogen compounds (1)
- Oxidation (1)
- PAH (1)
- PCB (1)
- PDB (1)
- PLS-DA (1)
- Passive sampling (1)
- Pentachlorophenol (1)
- Pflanzenwachstum (1)
- Phase I metabolism (1)
- Phosphous recovery (1)
- Photometric P determination (1)
- Polybrominated biphenyls (PBBs) (1)
- Polybrominated diphenyl ethers (PBDEs) (1)
- Polycyclic aromatic hydrocarbons (1)
- Polymer (1)
- Polypropylene (1)
- Polystyrene (1)
- Polyurethane (1)
- Polyurethanes (1)
- Predicting sites of metabolism (1)
- Probe (1)
- Probenahme (1)
- Process water (1)
- Proficiency Testing (1)
- Proficiency test (1)
- Pulverization (1)
- Pumpprobe (1)
- Pyrolysis (1)
- QM (1)
- Quality assurance (1)
- Qualitätsmanagement (1)
- Qualitätssicherung (1)
- R factor = 0.043 (1)
- Rainwater (1)
- Raman imaging (1)
- Rate matrix (1)
- Rearrangement (1)
- Reference material (1)
- Reference organisms (1)
- Referenzmaterial (1)
- Referenzmaterialien (1)
- Regulation (1)
- Remediation (1)
- Reproducibility (1)
- Ring test (1)
- Ring test structure (1)
- SEC (1)
- SPME (1)
- Safety (1)
- Sample (1)
- Sediment (1)
- Shelf life (1)
- Simulation (1)
- Single-crystal X-ray study (1)
- Sniffer dogs (1)
- Society of hair testing (1)
- Software (1)
- Sonication (1)
- Sorption (1)
- Stabilisation (1)
- Stability (1)
- Stakeholders (1)
- Standardisation (1)
- Standardization (1)
- Static headspace (1)
- Statistical thermodynamics (1)
- Statistics (1)
- Support vector machines (1)
- Suspended organic matter (1)
- Synthesis (1)
- Synthetic air (1)
- T = 273 K (1)
- TBBPA-dbpe (1)
- TED-GC-MS (1)
- TFA (1)
- Thermal degradation (1)
- Thermo-desorption (1)
- Total organic carbon (1)
- Total petroleum hydrocarbons (1)
- Trace elements (1)
- Traceability (1)
- Trichloroethene (1)
- Umweltanalytik (1)
- Urine (1)
- Vinyl chloride (1)
- Waste (1)
- Waste ecotoxicity (1)
- Waste legislation (1)
- Waste wood (1)
- Wastewater (1)
- X-ray (1)
- X-ray analysis (1)
- X-ray structure analyses (1)
- Zinc (1)
- dog training (1)
- herbs (1)
- reference materials, (1)
- scent dog (1)
- smell (1)
- training model (1)
- wR factor = 0.121 (1)
Organisationseinheit der BAM
- 1 Analytische Chemie; Referenzmaterialien (19)
- 1.7 Organische Spuren- und Lebensmittelanalytik (19)
- 4 Material und Umwelt (4)
- 6 Materialchemie (4)
- 5 Werkstofftechnik (3)
- 6.3 Strukturanalytik (3)
- 4.3 Schadstofftransfer und Umwelttechnologien (2)
- 5.3 Polymere Verbundwerkstoffe (2)
- 6.6 Physik und chemische Analytik der Polymere (2)
- 1.2 Biophotonik (1)
Paper des Monats
- ja (1)
A procedure for the quantification of the PCB marker congeners 28, 52, 101, 138, 153, 180 in plastic waste form the recycling of cables in the range of content between 0.1 mg kg-1 and 20 mg kg-1 was validated. Representative reference materials for laboratory analyses were produced using granulates from different recycling processes. The method development included aspects of grinding, sieving, homogenising as well as the comparison of extraction methods and chromatographic conditions. The validated procedure foresees grinding of the technical sample to an upper particle size limit of 0.50 mm followed by extraction with an unpolar solvent such as n-hexane and gas chromatographic determination. LOD and LOQ for individual congeners ranged between 0.01 mg kg-1 and 0.08 mg kg-1. Electron capture detection (ECD) and mass selective detection (MS) were equivalent if chromatographic conditions were appropriately selected. The application of MS was advantageous in presence of significant amounts of interfering components which have been found in some cables.
Three reference materials containing the marker congeners in the range of 0.1 mg kg-15 mg kg-1 were submitted to a final validation intercomparison with 23 selected field laboratories using the developed method. Relative reproducibility standard deviations varied between 15% and 33%.
Due to the utilisation of 1,1,2-trichlorotrifluoroethane (CFE) as extraction solvent the IR-spectrometric determination of total petrol hydrocarbon (TPH) in soil according to ISO/TR 11046 has been replaced by gas chromatography/flame ionisation detection (GC/FID) after extraction with a halogen-free solvent according to ISO/DIS 16703:2001. The results obtained with both methods by field laboratories in three proficiency testing (PT) rounds are compared. The consensus means obtained with GC/FID are typically 10%-20% (ranging between 0% and 25%) higher than those found with IR-spectroscopy. On the contrary, coefficients of variation (CV) are roughly double in case of GC/FID and are briefly discussed against the background of the Horwitz equation.
The concentration of contaminants in groundwater samples can be decreased by degradation in the time course between field sampling and quantification in the laboratory, especially in samples from sites where degradation activity is enhanced by remediation measures. The sampling sites covered a variety of priority organic pollutants such as volatile aromatic and chlorinated compounds, phenols and petroleum hydrocarbons and different remediation strategies such as anaerobic and aerobic microbial in situ degradation, in situ chemical oxidation, and on-site purification with biological treatment. The stability of the contaminants' concentration was investigated over a time range of several hours without cooling in the autosampler of the analytical equipment (short term) and over several days of storage until analysis (long term). A number of stabilisation techniques suggested in international standards ISO 5667-3:2013 and ASTM D6517:2000 were compared both with regard to short term and long term stabilisation of the contaminants and their practicability for field sampling campaigns. Long term storage turned out to be problematic for most compound groups even under cooling. Short term stability was problematic also for volatiles such as benzenic aromates, naphthalene and volatile organic halogenated compounds to be analysed by headspace gas chromatography. Acidification (pH <2) was sufficient to prevent degradation of benzenic aromates, naphthalene, phenols and petrol hydrocarbons for up to seven days. The use of acids was not applicable to stabilise volatiles in waters rich in carbonates and sulphides due to stripping of the volatiles with the liberated gases. The addition of sodium azide was successfully used for stabilisation of volatile organic halogenated compounds.
Two different hair reference materials, one produced from authentic hair displaying an ethyl glucuronide (EtG) content of about 25 pg/mg and one obtained by fortification of blank hair to an EtG level of 85 pg/mg were submitted to accelerated aging between 4 degrees C and 60 degrees C for periods between one and 24 months. Subsequently, the EtG content was determined in the aged samples and untreated reference samples stored at -22 degrees C under repeatability conditions following the so-called isochronous approach. The EtG content remained stable even at 40 degrees C for 24 months and at 60 degrees C over six months. This is in contrast to many organic analytes contained in trace concentrations in diverse matrices. A slight but significant increase of the recovered EtG in case of authentic hair samples having been exposed for 24 months between 4 degrees C and 60 degrees C may be due to a temperature-driven process that allows increased recoveries of the physiologically embedded EtG.
ISO Guide 35 deals with RM stability issues and scrutinizes the evaluation of stability testing results under the assumption that either there is no trend at all (a rather rare situation), or any observed deterministic change is insignificant and thus can be neglected. However, market demands for reliable reference materials are obviously not limited to stable or at least seemingly stable materials. In many analytical applications, analytes and measurands under consideration are known, or at least suspected, to be unstable on time scales that may vary widely from measurand to measurand. The Federal Institute for Materials Research and Testing (BAM) has developed (and successfully uses) an integrated approach in its certification practice. The approach is based on an initial stability study and subsequent post-certification monitoring. Data evaluation is model-based and takes advantage of all information collected in the stability testing scheme(s). It thus allows one to deal with any kind of instability observed, to assess limiting time intervals at any stress condition in the range tested, to estimate a final expiry date for materials with detected instabilities or the maximum admissible re-testing interval for seemingly stable materials, and to assess maximum admissible stress loads during delivery of the material to the customer. The article describes (and exemplifies) typical study layout, the model selection, and the integrated data assessment.
This paper describes Food-MetNet, a coordinated preparatory initiative to establish the European Metrology Network on Food Safety (EMN-FS). Food-MetNet aims to establish a long-term ongoing dialogue between the metrology community and relevant stakeholders, in particular, European Union Reference Laboratories (EURLs), National Reference Laboratories (NRLs) and the Joint Research Centre (JRC). This dialogue is meant to support the collection of needs from stakeholders, the take-up of metrological research output and the development of the roadmaps needed to navigate future research.
Levels of α-, β-, and γ-hexabromocyclododecane (HBCD) were determined in pooled eggs from herring gulls (Larus argentatus) sampled on three bird sanctuaries near the German North Sea coast between 1988 and 2008 (Mellum and Trischen) and the German Baltic Sea coast between 1998 and 2008 (Heuwiese) and archived by the German Environmental Specimen Bank. Pressurized fluid extraction, gel permeation chromatography, and LCMS/MS using 13C12-labelled isotope standards and a chiral column were applied. α-HBCD was the dominating diastereomer and ranged between 3.7 and 107 ng g-1 lw while β- and γ-HBCD were throughout close to LOQ. The highest α-HBCD concentration was found in eggs from Mellum sampled in the year 2000. Interestingly, HBCD in eggs from the three islands displayed similar time courses with levels increasing to a peak contamination around 2000 and decreasing levels ever since. Chiral signatures of α-HBCD in eggs differed among the islands but indicated a preferential enrichment of the first eluting enantiomer (-)-α-HBCD.
The interlaboratory variability in the quantification of adsorbable organically bound halogens (AOX) in industrially contaminated soil is presented. Three consecutive rounds of a proficiency testing scheme, in which between 88 and 119 routine laboratories participated, yielded relative reproducibility standard deviations between 7 and 20% at AOX contents between 10.9 and 268 mg kg-1. Nineteen laboratories with established proficiency were invited to participate in the certification of the AOX content in three soil reference materials meant for the internal quality control in analytical laboratories. The certified values are (1349 ± 59) mg kg-1, (80 ± 7) mg kg-1 and (102 ± 8) mg kg-1, respectively.
The increasing request for hair ethyl glucuronide (HEtG) in alcohol consumption monitoring according to cut-off levels set by the Society of Hair Testing (SoHT) has triggered a proficiency testing program based on interlaboratory comparisons (ILC). Here, the outcome of nine consecutive ILC rounds organised by the SoHT on the determination of HEtG between 2011 and 2017 is summarised regarding interlaboratory reproducibility and the influence of procedural variants. Test samples prepared from cut hair (1 mm) with authentic (in-vivo incorporated) and soaked (in-vitro incorporated) HEtG concentrations up to 80 pg/mg were provided for 27–35 participating laboratories. Laboratory results were evaluated according to ISO 5725-5 and provided robust averages and relative reproducibility standard deviations typically between 20 and 35% in reasonable accordance with the prediction of the Horwitz model. Evaluation of results regarding the analytical techniques revealed no significant differences between gas and liquid chromatographic methods In contrast, a detailed evaluation of different sample preparations revealed significantly higher average values in case when pulverised hair is tested compared to cut hair. This observation was reinforced over the different ILC rounds and can be attributed to the increased acceptance and routine of hair pulverisation among laboratories. Further, the reproducibility standard deviations among laboratories performing pulverisation were on average in very good agreement with the prediction of the Horwitz model. Use of sonication showed no effect on the HEtG extraction yield.
Microplastics are increasingly entering marine, limnic and terrestrial ecosystems worldwide, where they sorb hydrophobic organic contaminants. Here, the sorption behavior of the fuel-related water contaminants benzene, toluene, ethyl benzene and xylene (BTEX) and four tertiary butyl ethers to virgin and via UV radiation aged polypropylene (PP) and polystyrene (PS) pellets was investigated. Changes in material properties due to aging were recorded using appropriate polymer characterization methods, such as differential scanning calorimetry, Fourier transform infrared spectroscopy, gel permeation chromatography, X-ray photoelectron spectroscopy, and microscopy.
Pellets were exposed to water containing BTEX and the ethers at 130-190 mg/L for up to two weeks.
Aqueous sorbate concentrations were determined by headspace gas chromatography. Sorption to the polymers was correlated with the sorbate's Kow and was significant for BTEX and marginal for the ethers.
Due to substantially lower glass transition temperatures, PP showed higher sorption than PS. Aging had no effect on the sorption behavior of PP. PS sorbed less BTEX after aging due to an oxidized surface layer.
The validation of a robust quantification procedure for EtG in hair using GC–NCI–MS is presented. Aqueous extraction is followed by complete lyophylization of the extract and derivatization with pentafluoropropionic anhydride (PFPA) under controlled temperature and duration. Clean-up of extracts was dispensable and standard single quadrupole MS displayed sufficient selectivity and sensitivity. The method displayed a wide linearity range and enabled LOD of 0.68 pg/mg, LOQ of 2.4 pg/mg, and precision below 8.12%. Since EtG was seen to display prolonged stability in the aqueous extracts and after derivatization with PFPA this straightforward procedure allows a routine throughput of large quantities of samples with little proneness to procedural scatter of results. The method was applied to demonstrate the homogeneity of two hair reference materials with mean EtG contents of 8.48 pg/mg and 22.0 pg/mg. Aside from the application in homogeneity studies of hair reference materials predominantly in the concentration range of 10–50 pg/mg the method was also designed for daily routine quantification of real-world sample with regard to drinking behavior assessment.
A number of currently recommended sampling techniques for the determination of hydrogen in contaminated groundwater were compared regarding the practical proficiency in field campaigns. Key characteristics of appropriate sampling procedures are reproducibility of results, robustness against varying field conditions such as hydrostatic pressure, aquifer flow, and biological activity. Laboratory set-ups were used to investigate the most promising techniques. Bubble stripping with gas sampling bulbs yielded reproducible recovery of hydrogen and methane which could be verified for groundwater sampled in two field campaigns. The methane content of the groundwater was confirmed by analysis of directly pumped samples thus supporting the trueness of the stripping results. Laboratory set-ups and field campaigns revealed that bubble stripping of hydrogen may be restricted to the type of used pump. Concentrations of dissolved hydrogen after bubble stripping with an electrically driven submersible pump were about one order of magnitude higher than those obtained from diffusion sampling. The gas chromatographic determination for hydrogen and methane requires manual injection of gas samples and detection by a pulsed discharge detector (PDD) and allows limits of quantification of 3 nM dissolved hydrogen and 1 µg L-1 dissolved methane in groundwater. The combined standard uncertainty of the bubble stripping and GC/PDD quantification of hydrogen in field samples was 7% at 7.8 nM and 18% for 78 nM.
Thermo-Desorption Gas Chromatography-Mass Spectrometry (TD-GC-MS) was used to investigate the thermal degradation of two different polyurethanes (PU). PU samples were heated at different heating rates and the desorbed products were collected in a cold injection system and thereafter submitted to GC-MS. Prospects and limitations of the detection and quantification of semi-volatile degradation products were investigated. A temperature dependent PU depolymerization was
found at temperatures above 200 °C proved by an increasing release of 1,4-butanediol and methylene diphenyl diisocyanate (MDI) representing the main building blocks of both polymers. Their release was monitored quantitatively based on external calibration with authentic compounds. Size Exclusion Chromatography (SEC) of the residues obtained after thermodesorption confirmed the initial competitive degradation mechanism indicating an equilibrium of crosslinking and depolymerization as previously suggested. Matrix-Assisted Laser Desorption Ionization (MALDI) mass spectrometry of SEC fractions of thermally degraded PUs provided additional hints on degradation mechanism.
Towards the standardization of biochar analysis: the COST action TD1107 interlaboratory comparison
(2016)
Biochar produced by pyrolysis of organic residues is increasingly used for soil amendment and many other applications. However, analytical methods for its physical and chemical characterization are yet far from being specifically adapted, optimized, and standardized. Therefore, COST Action TD1107 conducted an interlaboratory comparison in which 22 laboratories from 12 countries analyzed three different types of biochar for 38 physical–chemical parameters (macro- and microelements, heavy metals, polycyclic aromatic hydrocarbons, pH, electrical conductivity, and specific surface area) with their preferential methods. The data were evaluated in detail using professional interlaboratory testing software. Whereas intralaboratory repeatability was generally good or at least acceptable, interlaboratory reproducibility was mostly not (20% < mean reproducibility standard deviation < 460%). This paper contributes to better comparability of biochar data published already and provides recommendations to improve and harmonize specific methods for biochar analysis in the future.
Fuel contamination of soils display complex and variable hydrocarbon mixtures with different volatility and toxicity characteristics. A recently suggested headspace procedure for the structure-based quantification of volatile hydrocarbons is evaluated regarding repeatability, reproducibility, and practical robustness. Three aliphatic and three aromatic fractions covering the boiling range between 69 and 216°C were defined as summation parameters by their respective equivalent carbon number ranges. A standard mixture of 35 aliphatic and aromatic hydrocarbons was used for calibration on basis of selected mass fragments specific for the aliphatics and aromatics, respectively. Two standard soils were fortified with the standard mixture or different fuels, respectively, and submitted to the analytical procedure. Limit of detection (LOD) and limit of quantification (LOQ) were for all fractions lower than 0.1 and 0.3 mg/kg, respectively. Analyte recovery was linear up to between 20 and 110 mg hydrocarbons/kg soil depending on the fraction. Hydrocarbon recovery ranged between 80% and 110% depending on the fraction and the repeatability was typically better than 10%. Finally, the impact of extraction solvent variation, column solid-phase polarity, and alternative summation of fractions were investigated. The procedure was applied to liner samples taken from a site contaminated with aviation fuel and its practicability is discussed.