Filtern
Erscheinungsjahr
Dokumenttyp
Referierte Publikation
- ja (76) (entfernen)
Schlagworte
- Interlaboratory comparison (8)
- Gas chromatography (6)
- Extraction (5)
- Analysis (4)
- Brominated flame retardant (4)
- Groundwater (4)
- HPLC-MS/MS (4)
- Boden (3)
- Breath (3)
- Chiral separation (3)
- Mass spectrometry (3)
- Microplastics (3)
- Proficiency testing (3)
- VOC (3)
- Volatile organic compounds (3)
- Volatilome (3)
- A549 (2)
- Alcohol marker (2)
- Aniline (2)
- Certification (2)
- Certified reference materials (2)
- Chloroanilines (2)
- Degradation (2)
- Diastereomers (2)
- Ethyl glucuronide (2)
- Flame retardant (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)
- 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)
- Absolute configuration (1)
- Acrylamid (1)
- Active sampling (1)
- Adsorption (1)
- Analysis and identification (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)
- Chemometrics (1)
- Collaborative trial (1)
- Combustion (1)
- Conformational chirality (1)
- Contaminated site (1)
- Contamination (1)
- Crosslinking (1)
- Crystal structure (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)
- 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)
- Flammschutzmittel (1)
- Fluoroacetic acid (1)
- Food (1)
- Fuel (1)
- Fungi (1)
- Furfurals (1)
- GC-AED (1)
- GC/MS (1)
- GC/MS-MS (1)
- GCMS (1)
- Gaschromatographie (1)
- Gasoline (1)
- Ground water (1)
- Groundwater monitoring (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)
- LC-MS (1)
- LC/MS-MS (1)
- Lung cancer cell culture (1)
- MOSH/MOAH (1)
- Marker (1)
- Measurement uncertainty (1)
- Metabolism of HBCD (1)
- Metaboliten (1)
- Metal-organic complexes (1)
- Methane (1)
- Method development (1)
- Method validation (1)
- Micropulverized extraction (1)
- Mineral oil hydrocarobons (1)
- Mineralölkohlenwasserstoffe (1)
- Minor isomers (1)
- Moisture (1)
- Molecular dynamics (1)
- Molecular modeling (1)
- Molecular simulation (1)
- Municipal sludge (1)
- NPE (1)
- Nation metrology institutes (1)
- Near Infrared Spectroscopy (1)
- Odour discrimination task (1)
- Optical rotation (1)
- Organohalogen compounds (1)
- Oxidation (1)
- PAH (1)
- PCB (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)
- Process water (1)
- Proficiency Testing (1)
- Proficiency test (1)
- Pulverization (1)
- Pyrolysis (1)
- QM (1)
- R factor = 0.043 (1)
- Rainwater (1)
- Raman imaging (1)
- Rearrangement (1)
- Reference material (1)
- Reference organisms (1)
- Regulation (1)
- Remediation (1)
- Reproducibility (1)
- Ring test (1)
- Ring test structure (1)
- Ringversuch (1)
- SEC (1)
- SPME (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)
- 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)
- Thyroxin (1)
- Total organic carbon (1)
- Total petroleum hydrocarbons (1)
- Trace elements (1)
- Traceability (1)
- Trichloroethene (1)
- Urine (1)
- Vinyl chloride (1)
- Waste (1)
- Waste ecotoxicity (1)
- Waste legislation (1)
- Waste wood (1)
- X-ray (1)
- X-ray analysis (1)
- X-ray structure analyses (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 (18)
- 1.7 Organische Spuren- und Lebensmittelanalytik (18)
- 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)
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.
Microplastics can affect biophysical properties of the soil. However, little is known about the cascade of events in fundamental levels of terrestrial ecosystems, i.e., starting with the changes in soil abiotic properties and propagating across the various components of soil−plant interactions, including soil microbial communities and plant traits. We investigated here the effects of six different microplastics (polyester fibers, polyamide beads, and four fragment types: polyethylene, polyester terephthalate, polypropylene, and polystyrene) on a broad suite of proxies for soil health and performance of spring onion (Allium fistulosum). Significant changes were observed in plant biomass, tissue elemental composition, root traits, and soil microbial activities. These plant and soil responses to microplastic exposure were used to propose a causal model for the mechanism of the effects. Impacts were dependent on particle type, i.e., microplastics with a shape similar to other natural soil particles elicited smaller differences from control. Changes in soil structure and water dynamics may explain the observed results in which polyester fibers and polyamide beads triggered the most pronounced impacts on plant traits and function. The findings reported here imply that the pervasive microplastic contamination in soil may have consequences for plant performance and thus for agroecosystems and terrestrial biodiversity.
Soils are essential components of terrestrial ecosystems that experience strong pollution pressure. Microplastic contamination of soils is being increasingly documented, with potential consequences for soil biodiversity and function. Notwithstanding, data on effects of such contaminants on fundamental properties potentially impacting soil biota are lacking. The present study explores the potential of microplastics to disturb vital relationships between soil and water, as well as its consequences for soil structure and microbial function. During a 5-weeks garden experiment we exposed a loamy sand soil to environmentally relevant nominal concentrations (up to 2%) of four common microplastic types (polyacrylic fibers, polyamide beads, polyester fibers, and polyethylene fragments). Then, we measured bulk density, water holding capacity, hydraulic conductivity, soil aggregation, and microbial activity. Microplastics affected the bulk density, water holding capacity, and the functional relationship between the microbial activity and water stable aggregates. The effects are underestimated if idiosyncrasies of particle type and concentrations are neglected, suggesting that purely qualitative environmental microplastic data might be of limited value for the assessment of effects in soil. If extended to other soils and plastic types, the processes unravelled here suggest that microplastics are relevant long-term anthropogenic stressors and drivers of global change in terrestrial ecosystems.
Evidence for the formation of difluoroacetic acid in chlorofluorocarbon-contaminated ground water
(2019)
The concentrations of difluoroacetic acid (DFA) and trifluoroacetic acid (TFA) in rainwater and surface water from Berlin, Germany resembled those reported for similar urban areas, and the TFA/DFA ratio in rainwater of 10:1 was in accordance with the literature. In contrast, nearby ground water historically contaminated with 1,1,2-trichloro-1,2,2-trifluoroethane (R113) displayed a TFA/DFA ratio of 1:3. This observation is discussed versus the inventory of microbial Degradation products present in this ground water along with the parent R113 itself. A microbial Transformation of chlorotrifluoroethylene (R1113) to DFA so far has not been reported for environmental media, and is suggested based on well-established mammalian metabolic pathways.
The reliability in measurement results obtained during environmental monitoring is crucial for the assessment and further planning of remediation efforts on the respective contaminated sites by the responsible authorities. A case study concerned with groundwater contaminated with perchloroethylene, trichloroethylene and 1,1,2-trichlorotrifluoroethane including their degradation products which involves private contract laboratories and an independent provider of quality assurance (QA) is presented. The experience gained with biannual monitoring campaigns over 14 years indicates that the selection of contractors on basis of accreditation status and successful performance in interlaboratory comparisons are not sufficient. Rather the auditing of the contractors by the QA provider prior to each campaign and the crosschecking of selected monitoring samples by the QA provider led to a lasting improvement of reliability in the contractors' measurement results. A mean deviation of 20% from the reference value determined by the QA provider for the crosschecked samples was reached.
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.
A practical method for the quantification of
total purgeable organic sulfur (POS) in highly contaminated
groundwater is described. Volatile organic sulfur
compounds (VOSC) are purged from the water samples by
a stream of oxygen and combusted. The emerging sulfur
dioxide is absorbed in H2O2 and converted to sulfate which
is quantified by ion chromatography and reported as mass
sulfur equivalent. The overall limit of quantification is
0.03 mg l1. The content of POS is balanced with the total
VOSC determined by GC-AED after liquidliquid extraction.
Separate determination of the non-volatile organic
sulfur compounds by direct combustion of the water sample
and adsorption to charcoal yielded a mass balance of
the total sulfur content. Semi-quantitative GC-MS after
purge & trap accumulation revealed that the VOSC mixture
is composed of C1C4 alkyl sulfides. The implementation
of the developed methodology for the quantification of
VOSC as potential catalyst poison in a cleaning plant
for groundwater contaminated with volatile haloorganics
(VOX) is presented.
Three chromatographic procedures were investigated regarding their potential for the quantification of aniline and 19 of its methylated and chlorinated derivatives in groundwater. These methods were based on liquid-liquid-extraction in combination with gas chromatography and single quadrupole mass spectrometry (GC/MS) according to German standard DIN 38407-16:1999 and its extension using tandem mass spectrometry (GC/MS-MS), both following liquid-liquid extraction, and as third alternative the direct injection of the water sample into a liquid chromatograph coupled to tandem mass spectrometry (LC/MS-MS). Results were compared using fortified water and real-world contaminated groundwater used in an interlaboratory comparison. It could be shown that GC/MS and GC/MS-MS yielded results deviating less than 10% from each other while all three procedure displayed quantification results deviating less than 15% from the intercomparison reference values in case of each analyte in the concentration range between 1 and 45 µg L-1. Though GC/MS-MS displays a ten-fold higher sensitivity than single quadrupole GC/MS, the precision of both methods in the concentration range was similar. LC/MS-MS has the advantage of no further sample preparation due to the direct injection and leads for methylanilines and meta-, para- substituted chloroanilines to results sufficiently equivalent to the standardised GC/MS method. However, LC/MS-MS is not suitable for ortho-chloroaniline derivates due to significantly lower ion yields than meta- and para-substituted chloroanilines.
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.
Der Einsatz aktiver (Pumpprobennahme,
Schöpfprobennahme) und passiver (Diffusionsprobennahme)
Probennahmetechniken zur Gehaltsbestimmung von
LHKW sowie Ethen und Methan in Grundwasser wird aus
ordnungsbehördlicher Sicht hinsichtlich der Vergleichbarkeit
von Analysendaten untersucht. Am Beispiel einer Kontamination
mit Trichlorethen sowie 1,2-Dichlorethen und
Vinylchlorid kann deutlich gemacht werden, dass die Einsatzmöglichkeit
der passiven Probennahme durch unzureichende
Strömungsverhältnisse im Aquifer sowie biologische
Aktivität im Pegelrohr begrenzt ist. Der aktiven Probennahme
ist bei ungeklärten oder unzureichenden Strömungsverhältnissen
im Grundwasserleiter daher der Vorzug
zu geben. Das gaschromatographische Verfahren für Vinylchlorid
mittels Dampfraumtechnik wird um die Quantifizierung
von Methan und Ethen erweitert. Dabei werden für
die Bewertung von Altlasten relevante Bestimmungsgrenzen
von 0,1 µg/l (Vinylchlorid, Ethen) sowie 5 µg/l (Methan)
erreicht.
Aus der Validierung der Analysenmethode und den
Ergebnissen verschiedener Probennahmen werden Toleranzbereiche
für die Ergebnisse eines Grundwassermonitorings
abgeschätzt. Diese Streubreiten von Monitoring-
Ergebnissen sollten von Ingenieurbüros und zuständigen
Ordnungsbehörden bei der Bewertung der komplexen Abbauprozesse
eines LHKW-Grundwasserschadens beachtet
werden.
A novel approach for the simulation of host.guest systems by systematically scanning the host moleculefs orientations within the guest cavity is presented along with a thermodynamic strategy for determining preferential binding modes and corresponding optimal interaction energies between host and guest molecules. By way of example, the elution order of hexabromocyclododecane stereoisomers from high performance liquid chromatography separation on a permethylated β-cyclcodextrin stationary phase has been computed using classical molecular dynamics simulations with the explicit solvents water and acetonitrile. Comparison of estimated with experimental separation data reveals remarkable squared coefficients of correlation with R2=0.87 and a very high correlation RLOO2 . 0:72 using the leaveone-out cross-validation method and water as solvent. In particular, the approach presented shapes up as very robust in terms of the evaluated time range under consideration, reflecting well thermodynamic equilibria. These and further observations correlating with experimental results suggest the suitability of the underlying force fields and our multi-mode approach for the estimation of relative binding affinities for host–guest systems with unknown binding modes.
In recent years, an increasing trend towards investigating and monitoring the contamination of the environment by microplastics (MP) (plastic pieces < 5 mm) has been observed worldwide. Nonetheless, a reliable methodology that would facilitate and automate the monitoring of MP is still lacking. With the goal of selecting practical and standardized methods, and considering the challenges in microplastics detection, we present here a critical evaluation of two vibrational spectroscopies, Raman and Fourier transform infrared (FTIR) spectroscopy, and two extraction methods: thermal extraction desorption gas chromatography mass spectrometry (TED-GC-MS) and liquid extraction with subsequent size exclusion chromatography (SEC) using a soil with known contents of PE, PP, PS and PET as reference material. The obtained results were compared in terms of measurement time, technique handling, detection limits and requirements for sample preparation. The results showed that in designing and selecting the right methodology, the scientific question that determines what needs to be understood is significant, and should be considered carefully prior to analysis. Depending on whether the object of interest is quantification of the MP particles in the sample, or merely a quick estimate of sample contamination with plastics, the appropriate method must be selected. To obtain overall information about MP in environmental samples, the combination of several parallel approaches should be considered.
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.
Hexabromocyclododecane enantiomers: microsomal degradation and patterns of hydroxylated metabolites
(2011)
The degradation of the enantiomers of α-, β-, and γ-hexabromocyclododecane (HBCD) by phase I metabolism was investigated using induced rat liver microsomes. HBCD isomers were quantified using HPLC-MS/MS (ESI-) after separation on a combination of a reversed phase and a chiral analytical column. The degradation of all six isomers followed first-order kinetics and the estimated half-lives ranged from 6.3 min for both β-HBCD enantiomers to 32.3 min in case of (+)-γ-HBCD. (+)-α- and (–)-γ-HBCD displayed significantly shorter half-lives than their corresponding antipodes. It could be shown that this degradation led to a significant enrichment of the first eluting enantiomers (–)-α- and (+)-γ-HBCD. Individual patterns of mono- and dihydroxylated derivatives obtained from each α- and γ-HBCD enantiomer were seen to be distinctly characteristic. The patterns of monohydroxylated HBCD derivatives detected in liver and muscle tissues of pollack, mackerel and in herring gull eggs were largely similar to those observed in the in vitro experiments with rat liver microsomes. This enabled individual hydroxy-HBCDs to be assigned to their respective parent HBCD enantiomers.
HBCD stereoisomer pattern in mirror carps following dietary exposure to pure Gamma-HBCD enantiomers
(2010)
1,2,5,6,9,10-hexabromocyclododecane (HBCD), a widely used flame retardant, is an ubiquitous contaminant in
the environment. Still, only little is known about the distribution and behavior in the environment such as
bioaccumulation or biotransformation of HBCD stereoisomers. In order to investigate enrichment and possible
bioisomerization of HBCD stereoisomers, Mirror Carps were exposed to pure (+)- and (-)-γ-HBCD, randomly
sampled after a predefined specific period and subjected to enantiomer-specific determination of α-, β-, and γ-
HBCD. No evidence for the isomerization of HBCD stereoisomers was observed in Mirror Carp fillets.
Odor Perception by Dogs: Evaluating Two Training Approaches for Odor Learning of Sniffer Dogs
(2017)
In this study, a standardized experimental set-up with various combinations of herbs as odor sources was designed. Two training approaches for sniffer dogs were compared; first, Training with a pure reference odor, and second, training with a variety of odor mixtures with the target odor as a common denominator. The ability of the dogs to identify the target odor in a new context was tested. Six different herbs (basil, St. John’s wort, dandelion, marjoram, parsley, ribwort) were chosen to produce reference materials in various mixtures with (positive) and without (negative)chamomile as the target odor source. The dogs were trained to show 1 of 2 different behaviors, 1 for the positive, and 1 for the negative sample as a yes/no task. Tests were double blind with one sample presented at a time. In both training approaches, dogs were able to detect chamomile as the target odor in any presented mixture with an average sensitivity of 72% and a specificity of 84%. Dogs trained with odor mixture containing the target odor had more correct indications in the transfer task.
A Proof of Concept: Are Detection Dogs a Useful Tool to Verify Potential Biomarkers for Lung Cancer?
(2018)
Early and reliable diagnostic test is essential for effective therapy of lung cancer. Volatile organic compounds that are characteristic for cancer could serve as valuable biomarkers in cancer diagnosis. Both trace analytical and detection dog approaches give some evidence for the existence of such biomarkers. In this proof of concept, study dogs and trace analysis were implemented in combination to gain more information concerning cancer biomarkers. Two dogs were trained to distinguish between absorbed breath samples of lung cancer patients and healthy persons and succeeded with correct identification of patients with 9/9 and 8/9 and correct negative indications from of 8/10 and 4/10 samples from healthy individuals. A recent observational study found that breath samples from lung cancer patients showed an increase in 1-butanol, 2-butanone, 2-pentanone, and hexanal. Synthetic air samples were therefore fortified with these compounds and adsorbed to a fleece. Tested against breath samples from healthy probands, on presentation to the dogs these synthetic samples provoked an indication in three out of four samples. We were able to demonstrate that a combination of the natural nose of a dog and a trace analytic technique can be a valuable concept in the search for cancer biomarkers.
On-line coupled high performance liquid chromatography-gas chromatography-flame ionisation detection (HPLC-GC-FID) was used to compare the effect of hydrogen, helium and nitrogen as carrier gases on the chromatographic characteristics for the quantification of mineral oil hydrocarbon (MOH) traces in food related matrices. After optimisation of chromatographic parameters nitrogen carrier gas exhibited characteristics equivalent to hydrogen and helium regarding requirements set by current guidelines and standardisation such as linear range, quantification limit and carry over. Though nitrogen expectedly led to greater peak widths, all required separations of standard compounds were sufficient and humps of saturated mineral oil hydrocarbons (MOSH) and aromatic mineral oil hydrocarbons (MOAH) were appropriate to enable quantitation similar to situations where hydrogen or helium had been used. Slightly increased peak widths of individual hump components did not affect shapes and widths of the MOSH and MOAH humps were not significantly affected by the use of nitrogen as carrier gas. Notably, nitrogen carrier gas led to less solvent peak tailing and smaller baseline offset. Overall, nitrogen may be regarded as viable alternative to hydrogen or helium and may even extend the range of quantifiable compounds to highly volatile hydrocarbon eluting directly after the solvent peak.
Certified reference materials for organic contaminants in sewage sludge - a feasibility study
(2008)
As an answer to the re-evaluation of the European sludge directive, two novel reference materials for organic components in municipal sludge have been produced and test certified for AOX (absorbable organic halogens), PAH (polycyclic aromatic hydrocarbons), NPE (nonylphenol and nonylphenolethoxylates), DEHP (di(2-ethylhexyl)phthalate), bisphenol A, and BFR (brominated flame retardants). The materials were prepared from raw sludge without spiking or mixing of different sludges. The study demonstrated that the technique for the preparation of a suitable reference material, sufficiently homogenous and stable, and with concentration levels that answer the needs of the laboratories and the relevant authorities, can now be presented in detail. The results, furthermore, show there is a need for method validation and standardisation of the measurements of NPEs and certain BFR congeners, and that the development of the laboratory structure in Europe, with fewer and more specialised laboratories, might become a major obstacle when trying to find a sufficient number of laboratories being appropriately proficient for this kind of study in the future.