TY - JOUR A1 - Becker, Roland T1 - Non-invasive cancer detection using volatile biomarkers: Is urine superior to breath? JF - Medical Hypothesis N2 - In recent years numerous reports have highlighted the options of chemical breath analysis with regard to noninvasive cancer detection. Certain volatile organic compounds (VOC) supposedly present in higher amounts or in characteristic patterns have been suggested as potential biomarkers. However, so far no clinical application based on a specific set of compounds appears to exist. Numerous reports on the capability of sniffer dogs and sensor arrays or electronic noses to distinguish breath of cancer patients and healthy controls supports the concept of genuine cancer-related volatile profiles. However, the actual compounds responsible for the scent are completely unknown and there is no correlation with the potential biomarkers suggested on basis of chemical trace analysis. It is outlined that specific features connected with the VOC analysis in breath – namely small concentrations of volatiles, interfering background concentrations, considerable sampling effort and sample instability, impracticability regarding routine application - stand in the way of substantial progress. The underlying chemicalanalytical challenge can only be met considering the severe susceptibility of VOC determination to these adverse conditions. Therefore, the attention is drawn to the needs for appropriate quality assurance/quality control as the most important feature for the reliable quantification of volatiles present in trace concentration. Consequently, the advantages of urine as an alternative matrix for volatile biomarker search in the context of diagnosing lung and other cancers are outlined with specific focus on quality assurance and practicability in clinical chemistry. The headspace over urine samples as the VOC source allows adapting gas chromatographical procedures well-established in water analysis. Foremost, the selection of urine over breath as non-invasive matrix should provide considerably more resilience to adverse effects during sampling and analysis. The most important advantage of urine over breath is seen in the option to partition, dispense, mix, spike, store, and thus to dispatch taylor-made urine samples on demand for quality control measures. Although it is still open at this point if cancer diagnosis supported by non-invasively sampled VOC profiles will ultimately reach clinical application the advantages of urine over breath should significantly facilitate urgently required steps beyond the current proof-of-concept stage and towards standardisation. KW - VOC KW - Breath KW - Urine KW - Lung cancer KW - Volatile organic compounds PY - 2020 DO - https://doi.org/10.1016/j.mehy.2020.110060 VL - 143 SP - 110060 PB - Elsevier Ltd. AN - OPUS4-51066 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becker, Roland A1 - Altmann, Korinna A1 - Sommerfeld, Thomas A1 - Braun, Ulrike T1 - Quantification of microplastics in a freshwater suspended organic matter using different thermoanalytical methods – outcome of an interlaboratory comparison JF - Journal of Analytical and Applied Pyrolysis N2 - A sedimented freshwater suspended organic matter fortified with particles of polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET) was employed in an interlaboratory comparison of thermoanalytical methods for microplastics identification and quantification. Three laboratories performed pyrolysis gas chromatography-mass spectrometry (Py-GC-MS), three others provided results using thermal extraction desorption followed by gas chromatography coupled to mass spectrometry (TED-GC-MS). One participant performed thermogravimetry-infrared spectroscopy (TGA-FTIR) and two participants used thermogravimetry coupled to mass spectrometry (TGA-MS). Further participants used differential scanning microscopy (DSC), a procedure based on micro combustion calorimetry (MCC) and a procedure based on elemental analysis. Each participant employed a different combination of sample treatment, calibration and instrumental Settings for polymer identification and quantification. Though there is obviously room for improvements regarding the between-laboratory reproducibility and the harmonization of procedures it was seen that the participants Performing Py-GC-MS, TED-GC-MS, and TGA-FTIR were able to correctly identify all polymers and to report reasonable quantification results in the investigated concentration range (PE: 20.0 μg/mg, PP: 5.70 μg/mg; PS: 2.20 μg/mg, PET: 18.0 μg/mg). Although for the other methods limitations exists regarding the detection of specific polymers, they showed potential as alternative approaches for polymer quantification in solid environmental matrices. KW - Interlaboratory comparison KW - Microplastics KW - Suspended organic matter KW - Pyrolysis PY - 2020 DO - https://doi.org/10.1016/j.jaap.2020.104829 VL - 148 SP - 1 EP - 6 PB - Elsevier B.V. AN - OPUS4-50977 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becker, Roland A1 - Heyn, L. A1 - Jung, Christian T1 - Indoor exposure to airborne polycyclic aromatic hydrocarbons: A comparison of stir bar sorptive extraction and pump sampling JF - Engineering Reports N2 - Stir bar sorptive extraction (SBSE) was compared with standardized pump sampling regarding the prospects to assess airborne levels of polycyclic aromatic hydrocarbons (PAHs) in indoor environments. A historic railway water tower, which will be preserved as a technical monument for museum purposes, was sampled with both approaches because the built-in insulationmaterial was suspected to release PAHs to the indoor air. The 16 PAHs on the US EPA list were quantified using gas chromatography with mass spectrometric detection in filters from pump sampling after solvent extraction and on SBSE devices after thermal desorption. SBSEwas seen to sample detectable PAHmasseswith excellent repeatability and a congener pattern largely similar to that observed with pump sampling. Congener patterns were however significantly different from that in the PAH source because release from the insulation material is largely triggered by the respective congener vapor pressures. Absolute masses in the ng range sampled by SBSE corresponded to airborne concentrations in the ng L−1 range determined by pump sampling. Principle differences between SBSE and pump sampling as well as prospects of SBSE as cost-effective and versatile complement of pump sampling are discussed. KW - Polycyclic aromatic hydrocarbons KW - Adsorption KW - Extraction KW - Indoor air PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537427 DO - https://doi.org/10.1002/eng2.12419 VL - 3 IS - 12 SP - 1 EP - 10 PB - John Wiley & Sons Ltd. AN - OPUS4-53742 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becker, Roland A1 - Sauer, Andreas A1 - Bremser, Wolfram T1 - Fifteen years of proficiency testing of total petrol hydrocarbon determination in soil: a story of success JF - Accreditation and Quality Assurance N2 - The total petrol hydrocarbon (TPH) content in soil is determined by gas chromatographic separation and flame ionisation detection according to ISO 16703 in routine laboratories for about 20 years. The development of the interlaboratory variability observed with this analytical procedure over 15 years in a proficiency testing scheme conducted annually with more than 170 participants is evaluated in detail. A significant improvement of the reproducibility standard deviation among participants is observed over the years and attributed to an increasing familiarity with the procedure. Nevertheless, the determination of TPH in the environmentally relevant mass fraction range between 500 mg/kg and 10 000 mg/kg in soils or sediments is far from reaching the reproducibility standard deviations predicted by the Horwitz curve. It is seen that laboratories with sporadic participation tend to report higher bias, while a core group of laboratories participating on a regular basis arrived at reproducibility standard deviations below 20 %. Results from a given laboratory obtained on two different samples tend to be highly correlated in the same PT round indicating a sound repeatability. Expectedly, the within-laboratory correlation between results from consecutive rounds was considerably lower. However, results from consecutive rounds with a temporal distance of 1, 2 or 3 years revealed largely similar correlations which suggests that the within-laboratory reproducibility adjusts to a constant level at least after a period of 1 year. KW - Mineralölkohlenwasserstoffe KW - Boden KW - Ringversuch KW - Gaschromatographie KW - GC-FID KW - Eingnugsprüfung KW - Proficiency Testing PY - 2019 DO - https://doi.org/10.1007/s00769-019-01383-x SN - 0949-1775 SN - 1432-0517 VL - 24 IS - 4 SP - 289 EP - 296 PB - Springer AN - OPUS4-48419 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becker, Roland A1 - Scholz, Philipp A1 - Jung, Christian A1 - Weidner, Steffen T1 - Thermo-Desorption Gas Chromatography-Mass Spectrometry for investigating the thermal degradation of polyurethanes JF - Analytical Methods N2 - 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. KW - Thermo-desorption KW - Mass spectrometry KW - Polyurethanes KW - Thermal degradation PY - 2023 DO - https://doi.org/10.1039/D3AY00173C SN - 1759-9660 SP - 1 EP - 6 PB - Royal Society for Chemistry AN - OPUS4-57307 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becker, Roland A1 - Sporkert, F. A1 - Lô, I. A1 - Baumgartner, M. T1 - The determination of ethyl glucuronide in hair: Experiences from nine consecutive interlaboratory comparison rounds JF - Forensic Science International N2 - 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. KW - Ethyl glucuronide KW - Interlaboratory comparison KW - Proficiency testing KW - Society of hair testing KW - Reproducibility KW - Pulverization PY - 2018 DO - https://doi.org/10.1016/j.forsciint.2018.04.025 SN - 0379-0738 SN - 1872-6283 VL - 288 SP - 67 EP - 71 PB - Elsevier AN - OPUS4-44881 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Souza Machado, A. A. A1 - Lau, C. W. A1 - Kloas, W. A1 - Bergmann, J. A1 - Bachelier, J. B. A1 - Faltin, E. A1 - Becker, Roland A1 - Görlich, A. S. A1 - Rillig, M. C. T1 - Microplastics can change soil properties and affect plant performance JF - Environmental Science and Technology N2 - 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. KW - Mikroplastik KW - Boden KW - Pflanzenwachstum PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-484181 DO - https://doi.org/10.1021/acs.est.9b01339 SN - 0013-936X SN - 1520-5851 VL - 53 IS - 10 SP - 6044 EP - 6052 PB - ACS AN - OPUS4-48418 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Souza Machado, A. A. A1 - Lau, C. W. A1 - Till, J. A1 - Kloas, W. A1 - Lehmann, A. A1 - Becker, Roland A1 - Rillig, M. C. T1 - Impacts of microplastics on the soil biophysical environment JF - Environmental Science and Technology N2 - 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. KW - Mikroplastik KW - Einfluß KW - Boden PY - 2018 DO - https://doi.org/10.1021/acs.est.8b02212 SN - 0013-936X SN - 1520-5851 VL - 52 IS - 17 SP - 9656 EP - 9665 PB - American Chemical Society AN - OPUS4-46547 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dorgerloh, Ute A1 - Becker, Roland A1 - Kaiser, M. T1 - Evidence for the formation of difluoroacetic acid in chlorofluorocarbon-contaminated ground water JF - Molecules N2 - 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. KW - Fluoroacetic acid KW - DFA KW - TFA KW - Rainwater KW - Ground water KW - Degradation of refrigerants PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475569 DO - https://doi.org/10.3390/molecules24061039 SN - 1420-3049 VL - 24 IS - 6 SP - 1039, 1 EP - 6 PB - MDPI CY - Basel AN - OPUS4-47556 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dorgerloh, Ute A1 - Becker, Roland A1 - Nehls, Irene T1 - Volatile hydrocarbons in contaminated soil: Robustness of fractional quantification using headspace gas chromatography-mass-spectrometry JF - Soil and sediment contamination N2 - 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. KW - Gasoline KW - Contaminated site KW - Equivalent carbon number KW - Fuel KW - Static headspace PY - 2018 DO - https://doi.org/10.1080/15320383.2018.1418287 SN - 1532-0383 SN - 1549-7887 VL - 27 IS - 1 SP - 1 EP - 12 PB - Taylor & Francis AN - OPUS4-43889 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -