TY - JOUR A1 - Alasonati, E. A1 - Fettig, I. A1 - Richter, Janine A1 - Philipp, Rosemarie A1 - Milačič, R. A1 - Sčančar, J. A1 - Zuliani, T. A1 - Tunç, M. A1 - Bilsel, M. A1 - Gören, A. A1 - Fisicaro, P. T1 - Towards tributyltin quantification in natural water at the Environmental Quality Standard level required by the Water Framework Directive N2 - The European Union (EU) has included tributyltin (TBT) and its compounds in the list of priority water pollutants. Quality standards demanded by the EU Water Framework Directive (WFD) require determination of TBT at so low concentration level that chemical analysis is still difficult and further research is needed to improve the sensitivity, the accuracy and the precision of existing methodologies. Within the frame of a joint research project “Traceable measurements for monitoring critical pollutants under the European Water Framework Directive” in the European Metrology Research Programme (EMRP), four metrological and designated institutes have developed a primary method to quantify TBT in natural water using liquid–liquid extraction (LLE) and species-specific isotope dilution mass spectrometry (SSIDMS). The procedure has been validated at the Environmental Quality Standard (EQS) level (0.2 ng L−1 as cation) and at the WFD-required limit of quantification (LOQ) (0.06 ng L−1 as cation). The LOQ of the methodology was 0.06 ng L−1 and the average measurement uncertainty at the LOQ was 36%, which agreed with WFD requirements. The analytical difficulties of the method, namely the presence of TBT in blanks and the sources of measurement uncertainties, as well as the interlaboratory comparison results are discussed in detail. KW - Tributyltin KW - Water Framework Directive KW - Metrological traceability KW - ICP-MS KW - Isotope dilution PY - 2016 DO - https://doi.org/10.1016/j.talanta.2016.07.056 SN - 0039-9140 SN - 1873-3573 VL - 160 SP - 499 EP - 511 PB - Elsevier B.V. AN - OPUS4-37407 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bastuck, M. A1 - Baur, T. A1 - Richter, Matthias A1 - Mull, B. A1 - Schütze, A. A1 - Sauerwald, T. T1 - Comparison of ppb-level gas measurements with a metal-oxide semiconductor gas sensor in two independent laboratories N2 - In this work, we use a gas sensor system consisting of a commercially available gas sensor in temperature cycled operation. It is trained with an extensive gas profile for detection and quantification of hazardous volatile organic compounds (VOC) in the ppb range independent of a varying background of other, less harmful VOCs and inorganic interfering gases like humidity or hydrogen. This training was then validated using a different gas mixture generation apparatus at an independent lab providing analytical methods as reference. While the varying background impedes selective detection of benzene and naphthalene at the low concentrations supplied, both formaldehyde and total VOC can well be quantified, after calibration transfer, by models trained with data from one system and evaluated with data from the other system. The lowest achievable root mean squared errors of prediction were 49 ppb for formaldehyde (in a concentration range of 20–200 ppb) and 150 μg/m³ (in a concentration range of 25–450 μg/m³) for total VOC. The latter uncertainty improves to 13 μg/m³ with a more confined model range of 220–320 μg/m³. The data from the second lab indicate an interfering gas which cannot be detected analytically but strongly influences the sensor signal. This demonstrates the need to take into account all sensor relevant gases, like, e.g., hydrogen and carbon monoxide, in analytical reference measurements. KW - Indoor air quality KW - Volatile organic compounds KW - Calibration transfer KW - Selective quantification KW - Inter-lab comparison PY - 2018 DO - https://doi.org/10.1016/j.snb.2018.06.097 SN - 0925-4005 VL - 273 SP - 1037 EP - 1046 PB - Elsevier B.V. AN - OPUS4-45609 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Roswag-Klinge, E. A1 - Klinge, A. A1 - Richter, Matthias A1 - Ziegert, C. T1 - Gesund bauen mit Naturbaustoffen N2 - Im Rahmen des EU-Forschungsvorhabens [H]house wurden Holz, Lehm und Naturfasern in Bezug auf Feuchtesorption und Schadstoffe untersucht und mit konventionellen Materialien verglichen. Weiter entwickelte Innenwandsysteme und Innendämmungen wurden ebenfalls untersucht. Auf dieser Basis wurden Holz- und Lehm-Bausysteme ohne Lüftungsanlage entwickelt und angewendet. KW - Naturbaustoffe KW - Feuchtesorption KW - Schadstoffsorption KW - Schadstoffemission KW - Lüftung PY - 2016 IS - 161 SP - 25 EP - 27 PB - Institut für Baubiologie + Nachhaltigkeit IBN CY - Rosenheim AN - OPUS4-38812 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shaik, A.-A. A1 - Richter, M. A1 - Kricheldorf, H. A1 - Krüger, Ralph-Peter T1 - New polymer syntheses - CIX. Biodegradable, alternating copolyesters of terephthalic acid, aliphatic dicarboxylic acids, and alkane diols N2 - Copolyesters with an alternating sequence of terephthalic acid and aliphatic dicarboxylic acids were prepared with three different methods. First, dicarboxylic acid dichlorides were reacted with bis(2-hydroxyethyl)terephthalate (BHET) in refluxing 1,2-dichlorobenzene. Second, the same monomers were polycondensed at 0-20 °C in the presence of pyridine. Third, dicarboxylic acid dichlorides and silylated BHET were polycondensed in bulk. Only this third method gave satisfactory molecular weights. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry revealed that the copolyesters prepared by the pyridine and silyl methods might have contained considerable fractions of cyclic oligoesters and polyesters despite the absence of transesterification and backbiting processes. The alternating sequences and thermal properties were characterized with 1H NMR spectroscopy and differential scanning calorimetry measurements, respectively. In agreement with the alternating sequence, all copolyesters proved to be crystalline, but the crystallization was extremely slow [slower than that of poly(ethylene terephthalate)]. A second series of alternating copolyesters was prepared by the polycondensation of silylated bis(4-hydroxybut- yl)terephthalate with various aliphatic dicarboxylic acid dichlorides. The resulting copolyesters showed significantly higher rates of crystallization, and the melting temperatures were higher than those of the BHET-based copolyesters. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3371-3382, 2001 KW - Poly(ethylene terephthalate) KW - Poly(butylene terephthalate) KW - Alternating sequence KW - Macrocycles KW - Crystallization KW - Biodegradable polyesters PY - 2001 DO - https://doi.org/10.1002/pola.1320 SN - 0360-6376 SN - 0887-624X VL - 39 IS - 19 SP - 3371 EP - 3382 PB - Wiley CY - Hoboken, NJ AN - OPUS4-2173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Miescher, K. A1 - Richter, Klaus A1 - Valberg, A. T1 - Farbe und Farbsehen, Beschreibung von Experimenten für die Farbenlehre PY - 1978 IS - 8 SP - 15 EP - 29 PB - Verl. Farbe + Design CY - Gaildorf AN - OPUS4-8951 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Richter, M. A1 - Trunschke, A. A1 - Bentrup, U. A1 - Brzezinka, Klaus-Werner A1 - Schreier, E. A1 - Schneider, M. A1 - Pohl, M.-M. A1 - Fricke, R. T1 - Selective Catalytic Reduction of Nitric Oxide by Ammonia over Egg-Shell MnOx/NaY Composite Catalysts N2 - A novel composite catalyst system for the selective catalytic reduction (SCR) of NOx by NH3 is described operating at temperatures lower than 470 K in the presence of water with NO conversions of 80–100% at space velocities of 30,000–50,000 h-1. The catalyst is prepared by egg-shell precipitation of MnO2 on the external surface of zeolite NaY. Structural and thermal stability of precipitated MnO2 as well as of the MnO2/NaY composite catalyst were characterized by N2 adsorption, X-ray diffraction, laser Raman spectroscopy, temperature-programmed reduction, and electron microscopy. MnO2 precipitated on zeolite NaY (15 wt% loading) retained its amorphous state up to calcination temperatures of 775 K. The zeolite component remained structurally intact. Calcination at higher temperatures destroyed the zeolite structure and transformed MnO2 into Mn3O4. DRIFT spectroscopic investigations revealed the presence of symmetric O=N—O—N=O species formally corresponding to N2O3 on the composite catalyst after contact with NO. Catalytic measurements under integral flow conditions showed that the catalyst performance is associated with a close coupling of nitrite formation and its drain off from equilibria with NO/NO2 and nitrate by ammonia. Several results are in line with the “diazotation” mechanism, including NH3 protonation to NH4+, whereas prevailing Lewis acid sites should enable NH3 activation via amide species, thus leading to a parallel “amide/nitrosamide” SCR reaction route. The activity-temperature profile fulfills the requirements of a low-temperature NOx reduction catalyst for mobile diesel engines if an ammonia supply is implemented “on board,” e.g., by urea decomposition. PY - 2002 DO - https://doi.org/10.1006/jcat.2001.3468 SN - 0021-9517 SN - 1090-2694 VL - 206 SP - 98 EP - 113 PB - Acad. Press CY - San Diego, Calif. AN - OPUS4-1638 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Krom, I. A1 - Heikens, D. A1 - Horn, Wolfgang A1 - Wilke, Olaf A1 - Richter, Matthias A1 - Baldan, A. T1 - Metrological generation of SI-traceable gas-phase standards and reference materials for (semi-) volatile organic compounds N2 - EN 16516 sets specifications for the determination of emissions into indoor air from construction products. Reliable, accurate and International System of Unit (SI)-traceable measurement results of the emissions are the key to consumer protection. Such measurement results can be obtained by using metrologically traceable reference materials. Gas-phase standards of volatile organic compounds (VOCs) in air can be prepared by a variety of dynamic methods according to the ISO 6145 series. However, these methods are not always applicable for semi-VOCs (SVOCs) due to their high boiling point and low vapour pressure. Therefore, a novel dynamic gas mixture generation system has been developed. With this system gas-phase standards with trace level VOCs and SVOCs in air can be prepared between 10 nmol mol−1 and 1000 nmol mol−1. The VOCs and SVOCs in this study have normal boiling points ranging from 146 °C to 343 °C. Metrologically traceable reference materials of the gas-phase standard were obtained by sampling of the VOC gas-phase standard into Tenax TA® sorbent material in SilcoNert® coated stainless steel tubes. Accurately known masses between 10 ng and 1000 ng per VOC were sampled. These reference materials were used to validate the dynamic system. Furthermore, the storage and stability periods of the VOCs in the reference materials were determined as these are crucial characteristics to obtain accurate and SI-traceable reference materials. In a round robin test (RRT), the reference materials were used with the aim of demonstrating the feasibility of providing SI-traceable standard reference values for SVOCs for interlaboratory comparison purposes. Based on the results from the validation, the storage and stability studies and the RRT, gas-phase standards and reference materials of VOCs and SVOCs with relative expanded uncertainties between 5% and 12% (k = 2) have been developed. These reference standards can be used as calibrants, reference materials or quality control materials for the analysis of VOC emissions. KW - SVOC KW - Dynamic calibration gas mixtures KW - Reference materials KW - Indoor air KW - Thermal desorption PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565978 DO - https://doi.org/10.1088/1361-6501/aca704 VL - 34 IS - 3 SP - 1 EP - 13 PB - IOP Publishing AN - OPUS4-56597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Richter, Matthias A1 - Horn, Wolfgang A1 - Juritsch, Elevtheria A1 - Klinge, A. A1 - Radeljic, L. A1 - Jann, Oliver T1 - Natural building materials for interior fitting and refurbishment - What about indoor emissions? N2 - Indoor air quality can be adversely affected by emissions from building materials, consequently having a negative impact on human health and well-being. In this study, more than 30 natural building materials (earth dry boards and plasters, bio-based insulation materials, and boards made of wood, flax, reed, straw, etc.) used for interior works were investigated as to their emissions of (semi-) volatile organic compounds ((S)VOC), formaldehyde, and radon. The study focused on the emissions from complete wall build-ups as they can be used for internal Partition walls and the internal insulation of external walls. Test chambers were designed, allowing the compounds to release only from the surface of the material facing indoors under testing Parameters that were chosen to simulate model room conditions. The emission test results were evaluated using the AgBB evaluation scheme, a procedure for the health-related evaluation of construction products and currently applied for the approval of specific groups of building materials in Germany. Seventeen out of 19 sample build-ups tested in this study would have passed this scheme since they generally proved to be low-emitting and although the combined emissions of multiple materials were tested, 50% of the measurements could be terminated before half of the total testing time. KW - Bio-based insulation KW - Earthen building materials KW - Volatile organic compounds KW - Semivolatile organic compounds KW - Radon PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519634 DO - https://doi.org/10.3390/ma14010234 VL - 14 IS - 1 (Special issue: Measurement of the environmental impact of materials) SP - 234-1 EP - 234-14 PB - MDPI CY - Basel AN - OPUS4-51963 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rhode, Michael A1 - Richter, Tim A1 - Mente, Tobias A1 - Mayr, P. A1 - Nitsche, A. T1 - Thickness and microstructure effect on hydrogen diffusion in creep‑resistant 9% Cr P92 steel and P91 weld metal N2 - Martensitic 9% Cr steels like P91 and P92 show susceptibility to delayed hydrogen assisted cracking depending on their microstructure. In that connection, effective hydrogen diffusion coefficients are used to assess the possible time-delay. Limited data on room temperature diffusion coefficients reported in literature vary widely by several orders of magnitude (mostly attributed to variation in microstructure). Especially P91 weld metal diffusion coefficients are rare so far. For that reason, electrochemical permeation experiments had been conducted using P92 base metal and P91 weld metal (in as-welded and heat-treated condition) with different thicknesses. From the results obtained, diffusion coefficients were calculated using to different methods, time-lag, and inflection point. Results show that, despite microstructural effects, the sample thickness must be considered as it influences the calculated diffusion coefficients. Finally, the comparison of calculated and measured hydrogen concentrations (determined by carrier gas hot extraction) enables the identification of realistic diffusion coefficients. KW - Creep-resistant steel KW - Diffusion KW - Hydrogen assisted cracking KW - Welding KW - Electrochemical permeation PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540645 DO - https://doi.org/10.1007/s40194-021-01218-9 SN - 0043-2288 SP - 1 EP - 16 PB - Springer Nature Switzerland AG AN - OPUS4-54064 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Matschat, Ralf A1 - Hassler, J. A1 - Richter, Silke A1 - Kleve, M. A1 - Dette, A. T1 - Multielement trace analysis of pure graphite powders using optical emission spectrometry coupled to a magnetically stabilized DC arc supplied with halogenating gases as chemical modifiers – a rapid and robust methodology N2 - A magnetically stabilized DC arc device, designed for operation with OES spectrometers was used to determine the elements Ag, Al, B, Ba, Be, Ca, Co, Cr, Cu, Fe, Ga, In, K, Li, Mg, Mn, Mo, Na, Nb, Ni, Si, Sn, Sr, Ti, V, Zr at trace levels of some μg kg−1 up to some 10 mg kg−1 in graphite powders. The coil for the generation of the homogeneous magnetic field was placed outside the closed arc chamber. The time programs of variable current strengths of the magnetic coil (up to 6 A) and of the arc (up to 17 A) which was burning in air were computer controlled. Halogenating gases (mainly CCl2F2, alternatively SF6 and NF3) were used as chemical modifiers to allow an effective release of the carbide forming trace elements. The mass flow controlled modifier gas was led through a special carrier electrode near the arc plasma. The emission radiation was guided by an optical fiber alternatively into two different ICP spectrometers in which the ICP torches were removed. The synergistic interaction of the magnetic field with the halogenating modifier gases resulted in a significant improvement in the analytical performance of the optimized analytical method. All our results for 22 trace elements were in good agreement with the means of an inter-laboratory comparison by BAM for certification of a pure graphite powder material; this holds also for our results for two other graphite materials. The optimized method showed an analytical performance suitable for comprehensive trace analysis of pure graphite. The instrumentation could be integrated into modern DC arc emission spectrometers to improve their analytical capabilities substantially. KW - Graphit KW - DC-Arc KW - High purity KW - Optical emission spectroscopy KW - Magnetically stabilized PY - 2018 DO - https://doi.org/10.1039/C7JA00387K SN - 1364-5544 SN - 0267-9477 VL - 33 IS - 3 SP - 468 EP - 480 PB - Royal Society of Chemistry AN - OPUS4-44398 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Morcillo, Dalia A1 - Winckelmann, Alexander A1 - Frick, Daniel A. A1 - Jacobsen, Lars A1 - Seger, Tino A1 - Florek, Stefan A1 - Richter, Silke A1 - Vogl, Jochen A1 - Recknagel, Sebastian A1 - Panne, Ulrich A1 - Abad Andrade, Carlos Enrique T1 - Lithium isotope ratio analysis of geological samples using atomic absorption spectrometry with improved spectral resolution N2 - This study introduces an improved spectrometric method with enhanced precision to determine isotope ratios in geological samples without chromatographic separation. Firstly, the improvement is achieved by increasing the spectral resolution of the spectrometer applied in well-known high-resolution continuum source atomic absorption spectrometry (HR-CS-AAS). The resulting resolving power and linear dispersion of the upgraded setup, which is denoted in the following as HR+CS-AAS, is well adapted to the line widths of the Li isotope components we investigated. Secondly, our proposed method combines optical absorption spectrometry with machine learning data analysis using an extreme gradient boosting algorithm (XGBoost). This method was applied to analyze certified geological reference materials with δLSVEC(7Li/6Li) (hereafter δ7Li) values ranging from −0.5 ‰ to 4.5 ‰. With a pixel related optical resolving power of λ/∆λ ≈ 780 000, we obtain precisions in δ7Li measurements from 1.0 ‰ to 2.5 ‰. The method is validated by comparing the results with multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), confirming its metrological compatibility. This work presents a fast, robust, and reliable method for δ7Li measurement in geological samples. KW - Isotope KW - High-resolution continuum source atomic absorption spectroscopy KW - Lithium KW - Machine learning KW - Echelle spectrometer PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611807 DO - https://doi.org/10.1016/j.sab.2024.107013 VL - 220 SP - 1 EP - 5 PB - Elsevier BV AN - OPUS4-61180 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -