TY - JOUR A1 - Heinrich, Sebastian A1 - Plettig, M. A1 - Klemm, E. T1 - Role of the Ti(IV)-superoxide species in the selective oxidation of alkanes with hydrogen peroxide in the gas phase on titanium silicalite-1: an in situ EPR investigation N2 - The interaction of TS-1 with gaseous hydrogen peroxide at temperatures above 373 K has been investigated by in situ EPR measurements. Treatment of TS-1 with hydrogen peroxide in the gas phase leads to a strong EPR signal, assigned to the Ti(IV)-superoxide species. In contrast to investigations with liquid hydrogen peroxide, here only one Ti(IV)-superoxide species could be detected in the EPR spectrum. The time constant of the reaction of the Ti(IV)-superoxide species detected by in situ EPR measurements was much larger than that observed for the rate of consumption of propane or propene via gas chromatographic analysis. Thus, we conclude that the Superoxide species may take part in the oxidation reaction (via side reactions or the formation of unselective products), but is probably not the main responsible species in the oxidation of propane or propene. KW - Titanium silicalite-1 KW - EPR KW - Oxidation KW - Hydrogen peroxide KW - Superoxide KW - Alkanes PY - 2011 DO - https://doi.org/10.1007/s10562-010-0534-6 SN - 1011-372X VL - 141 IS - 2 SP - 251 EP - 258 PB - Kluwer CY - Dordrecht AN - OPUS4-23553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heinrich, Sebastian A1 - Edeling, Florian A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Lange, T. A1 - Klemm, E. T1 - Catalyst as ignition source of an explosion inside a microreactor N2 - The present issue reports on a specific aspect of safety engineering of the heterogeneously catalysed oxidation of ethene in a continuous-flow microreactor. Conversion of ethene and the corresponding surface temperature of the catalyst were monitored for different reactor temperatures and total flow rates with a stoichiometric ethene/oxygen mixture for total oxidation. Safe operation of the highly exothermic oxidation was possible, but not in the whole parameter range. At high reactor temperatures and flow rates, ignition of an explosion inside the microreactor caused by a hot spot on the surface of the catalyst was observed for the first time. KW - Catalyst KW - Ethene KW - Explosions KW - Hot spot KW - Microstructure KW - Safety PY - 2012 DO - https://doi.org/10.1016/j.ces.2012.08.049 SN - 0009-2509 VL - 84 SP - 540 EP - 543 PB - Elsevier CY - Amsterdam AN - OPUS4-26782 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lange, T. A1 - Heinrich, Sebastian A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Klemm, E. T1 - Reaction engineering investigations of the heterogeneously catalyzed partial oxidation of o-xylene in the explosion regime using a microfixed bed reactor N2 - The heterogeneously catalyzed selective gas phase oxidation of o-xylene was investigated, using a microstructured fixed bed reactor, inside of the explosion regime. The reaction was carried out with high amounts of o-xylene in air and stoichiometric with oxygen using a V2O5/TiO2-catalyst prepared through grafting. There were no significant losses in the selectivity to phthalic anhydride observable, during the measurements in the explosion regime, with feed compositions of up to 7 vol% o-xylene. Also the space-time yield was up to 2.3 times higher in comparison to conventional reaction conditions. An increase of the selectivity to total oxidation products was observed at higher o-xylene concentrations between 10 and 25 vol% o-xylene, which possibly was caused by the formation of a hotspot. The investigation of the used catalyst revealed a thermally induced deactivation due to phase transition of anatase into rutil and formation of crystalline vanadium oxide. Despite that expected hotspot at high oxylene concentrations, there was no ignition or explosion of the gas mixture observable. KW - O-xylene oxidation KW - Phthalic anhydride KW - V2O5/TiO2-catalyst KW - Microfixed bed reactor KW - Explosion regime KW - Hotspot PY - 2012 DO - https://doi.org/10.1016/j.ces.2011.10.072 SN - 0009-2509 VL - 69 IS - 1 SP - 440 EP - 448 PB - Elsevier CY - Amsterdam AN - OPUS4-25463 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Heinrich, Sebastian A1 - Edeling, Florian A1 - Lange, T. A1 - Klemm, E. ED - Beyer, M. ED - Stolz, T. T1 - Zündung, Ausbreitung und Unterdrückung von Explosionen in einem Mikroreaktor N2 - Der vorliegende Beitrag behandelt spezifische Aspekte der Sicherheitstechnik bei heterogen katalysierten Oxidationsreaktionen. Ergebnisse von Explosionsuntersuchungen an Ethen-Sauerstoffgemischen in einem kontinuierlich betriebenen Mikroreaktor, die beispielsweise für den Ethylenoxidprozess relevant sind, werden vorgestellt. Der Anfangsdruck der untersuchten Eduktgemische lag zwischen 1000 hPa und 10000 hPa bei Anfangstemperaturen zwischen Umgebungstemperatur und einer Temperatur bis zu 673 K. Mikrostrukturierte Reaktoren bieten einen erweiterten Bereich von Betriebsbedingungen. Die Untersuchungen zielen auf den sicheren Betrieb eines Mikroreaktors bei Bedingungen, die bei konventionellen Reaktoren als innerhalb des Explosionsbereichs eingestuft werden, ab. In bestimmten Grenzen kann eine Unterdrückung von Explosionen in einem Mikroreaktor erreicht werden. Es ist jedoch nicht möglich, einen Mikroreaktor unter allen Bedingungen sicher zu betreiben. Aus diesen Gründen wurde die Explosionsausbreitung durch einen mikrostrukturierten Reaktor hindurch und die Zündung einer Gasphasenexplosion durch Hot-Spots in dem Reaktor untersucht. Die angewandten Untersuchungsmethoden sind Gegenstand aktueller Normungsaktivitäten. T2 - 13. BAM-PTB-Kolloquium zur chemischen und physikalischen Sicherheitstechnik CY - Braunschweig, Germany DA - 18.06.2013 KW - Micro Reactor KW - Explosion KW - Safety PY - 2013 SN - 978-3-95606-062-5 DO - https://doi.org/10.7795/210.20130910K SN - 1868-5838 SP - 90 EP - 98 AN - OPUS4-29849 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lange, T. A1 - Heinrich, Sebastian A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Klemm, E. T1 - Reaction engineering investigations of the partial oxidation of o-xylene in the explosion regime - microfixed bed versus catalyst coating N2 - The selective gas phase oxidation of o-xylene was investigated inside of the explosion regime using a microstructured reactor. The V2O5/TiO2 catalyst was used as microfixed bed and as catalyst coating. There were no significant losses of the selectivity to phthalic anhydride with feed compositions up to 7 vol % o-xylene observable. Above 7 vol % the selectivity decreased due to total oxidation, especially for the microfixed bed, which was probably caused by a hotspot. KW - Catalysis KW - Microreactors KW - Partial oxidation KW - Xylene KW - o-Xylene KW - Explosion regime PY - 2013 DO - https://doi.org/10.1002/cite.201200197 SN - 0009-286X SN - 1522-2640 VL - 85 IS - 4 SP - 461 EP - 466 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-30298 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lange, T. A1 - Neher, F. A1 - Klemm, E. A1 - Heinrich, Sebastian A1 - Balcazar Pust, Emilio A1 - Liebner, Christian A1 - Hieronymus, Hartmut T1 - Heterogeneous catalysis meets micro reactors: Partial oxidations in the explosion regime N2 - Investigations on primary, secondary and tertiary explosion protection have been performed for micro reactors with slit-like channels which are coated with catalyst. Ethene/oxygen mixtures have been used as model gas mixtures representing explosion group IIB (DIN EN ISO 16852). It could be shown that the explosion regime can be significantly reduced when using micro reactors (primary explosion protection). Furthermore, safe Operation inside the explosion regime is possible with micro reactors (secondary explosion protection), but, at certain conditions thermal runaway and ignition of detonations are possible. An unexpected behaviour has been found, because thermal runaway occurred when Volumetrie flow rate was increased. This behaviour is completely opposite to that of multi tube fixed bed reactors which show an increase of safety when increasing volumetric flow rate. Micro reactors can be constructed pressure-resistant even when detonations occur inside (tertiary explosion protection). For the example of o-xylene oxidation it could be shown that space time yield can be increased significantly when entering explosion regime. T2 - DGMK International conference - Selective oxidation and functionalization: Classical and alternative routes and sources CY - Berlin, Germany DA - 13.10.2014 PY - 2014 SN - 978-3-941721-44-9 VL - 2014-3 SP - 97 EP - 105 AN - OPUS4-31759 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Recknagel, Sebastian A1 - Bresch, Harald A1 - Kipphardt, Heinrich A1 - Resch-Genger, Ute A1 - Koch, Matthias A1 - Rosner, M. T1 - Trends in selected fields of reference material production N2 - For more than 110 years, BAM has been producing reference materials for a wide range of application fields. With the development of new analytical methods and new applications as well as continuously emerging more stringent requirements of laboratory accreditation with regard to quality control and metrological traceability, the demand and requirements for reference materials are increasing. This trend article gives an overview of general developments in the field of reference materials as well as developments in selected fields of application in which BAM is active. This includes inorganic and metal analysis, gas analysis, food and consumer products, and geological samples. In addition to these more traditional fields of application, developments in the areas of optical spectroscopy, particulary fluorescence methods, and nanomaterials are considered. T2 - 150 years BAM: Science with impact CY - Berlin, Germany DA - 01.01.2021 KW - Reference material KW - ISO REMCO KW - Gas analysis KW - Food KW - Nanomaterials KW - Fluorescence PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548407 DO - https://doi.org/10.1007/s00216-022-03996-7 SN - 1618-2642 SN - 1618-2650 VL - 414 IS - Topical collection: Analytical methods and applications in the materials and life sciences SP - 4281 EP - 4289 PB - Springer CY - Berlin AN - OPUS4-54840 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Recknagel, Sebastian A1 - Kipphardt, Heinrich A1 - Lange, Britta A1 - Hoppe, Marion T1 - Traceable analysis of impurities in metallic reference materials using GD-MS N2 - The traceabiiity requirements for certification analyses of reference materials are much more stringent than for routine analysis, where certified matrix reference materials (CRM) can be used for calibration and to establish traceabiiity. Although the ISO-Guides related to CRM production and certification are not fully clear concerning calibration, many established CRM-producers do not accept matrix-CRMs for calibration in case of certification analyses, e.g. to avoid circular reasoning. These requirements limit the methods used for certification to those that can be calibrated using Standards of known high purity and stoichiometry or mixtures of such Standards. Powerful solid sampling techniques such as glow discharge mass spectrometry (GD-MS) or spark-optical emission spectrometry (SOES), where usually compact CRMs are used for calibration, seem not be applicable for certification analyses. Especially GD-MS is a powerful tool for trace element determination of solid samples. Beside metallic impurities the use of specific gas mixtures enables also the determination of interesting nonmetallic impurities such as sulfur and phosphorus. Within BAM a calibration approach, was developed which enables to use mixtures of Standards of known high purity and stoichiometry also for GD-MS. Analogue to matrix adaption in solution based techniques, the calibration approach is based on doped pressed powder pellets. Approach and application on the certification analyses of copper and Steel CRMs are presented. T2 - CETAS 2011 - 8th International workshop on progress in analytical chemistry & materials characterisation in the steel and metal industries CY - Luxembourg, Luxembourg DA - 17.05.2011 PY - 2011 IS - OC53 SP - 361 EP - 365 AN - OPUS4-23762 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kipphardt, Heinrich A1 - Dudzus, Thomas A1 - Meier, Klaus A1 - Recknagel, Sebastian A1 - Hedrich, Martina A1 - Matschat, Ralf T1 - Measurement of oxygen and nitrogen in high purity metals used as national standards for elemental analysis in Germany by classical carrier gas hot extraction (HE) and HE after activation with photons N2 - The special importance of the analysis of non-metals in high purity metals, which will serve as national standards for elemental analysis in Germany, is illustrated for oxygen and nitrogen. The typical range of the mass fraction of oxygen and nitrogen in these materials is below 10.MU.g/g, often close to 1.MU.g/g. The two methods applied at BAM for these measurements are classical carrier gas hot extraction (HE) and carrier gas hot extraction after activation with photons (PAA-HE). The approach, the methods and their advantages and limitations are discussed. Comparative results from the measurement of oxygen and nitrogen in Cu, Fe, Ga, Pb, Sn and W are presented. (author abst.) T2 - 8th International Conference on Ultra-High Purity Base Metals (UHPM-2001) CY - Berlin, Germany DA - 2001-06-25 KW - Oxygen determination KW - Nitrogen determination KW - High purity metals KW - Carrier gas hot extraction KW - Photon activation analysis PY - 2002 DO - https://doi.org/10.2320/matertrans.43.98 SN - 1345-9678 SN - 1347-5320 VL - 43 IS - 2 SP - 98 EP - 100 PB - Japan Institute of Metals CY - Sendai AN - OPUS4-1361 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Matschat, Ralf A1 - Dudzus, Thomas A1 - Meier, Klaus A1 - Recknagel, Sebastian A1 - Kipphardt, Heinrich A1 - Hedrich, Martina ED - Hirschfeld, D. T1 - Messung von Sauerstoff und Stickstoff mit klassischer Trägergasheißextraktion und Trägergasheißextraktion nach Aktivierung mit Photonen für die nationalen primären Kalibriernormale T2 - 8. Symposium Nichtmetalle in Metallen - NIM ; 8. Tagung des Gemeinschaftsausschusses "Nichtmetalle in Metallen" der GDMB CY - Münster, Deutschland DA - 2000-03-16 PY - 2000 SN - 3-9806913-1-4 SP - 19 EP - 27 PB - GDMB, Ges. für Bergbau, Metallurgie, Rohstoff- und Umwelttechnik CY - Clausthal-Zellerfeld AN - OPUS4-915 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Matschat, Ralf A1 - Kipphardt, Heinrich A1 - Recknagel, Sebastian A1 - Noack, Siegfried ED - Abiko, K. ED - Takaki, S. T1 - Activities of Division "Inorganic Chemical Analysis; Reference Materials" of BAM in the Field of Analysis of Metals T2 - 9th international conference on ultrahigh-purity base metals CY - Sendai, Japan DA - 2002-10-14 PY - 2002 SP - 297 EP - 302 CY - Sendai AN - OPUS4-1602 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kipphardt, Heinrich A1 - Dudzus, Thomas A1 - Meier, Klaus A1 - Recknagel, Sebastian A1 - Hedrich, Martina A1 - Matschat, Ralf T1 - The measurement of O and N by classical carrier gas hot extraction (HE) - Carrier gas hot extraction after activation with photons T2 - CENAM CY - Mexico City, Mexico DA - 2002-01-28 PY - 2002 AN - OPUS4-1610 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kipphardt, Heinrich A1 - Recknagel, Sebastian T1 - Measurement of Nitrogen in Steel by Carrier Gas Hot Extraction - a Challenge in Calibration T2 - 6th International Workshop on progress in analytical chemistry in the steel and metals industries CY - Luxembourg, Luxembourg DA - 2002-05-14 PY - 2002 SP - 1(?) AN - OPUS4-1629 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Merchel, Silke A1 - Dudzus, Thomas A1 - Ecker, Klaus A1 - Hedrich, Martina A1 - Kipphardt, Heinrich A1 - Recknagel, Sebastian T1 - Viele (BAM-) Wege führen zu den leichten Elementen T2 - 12. Jahrescolloquium "Analyse von Feststoffen unterschiedlicher Materialien aus Industrie und Umwelt" CY - Berlin, Deutschland DA - 2002-11-19 PY - 2002 SP - 1(?) AN - OPUS4-2024 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Recknagel, Sebastian A1 - Noack, Siegfried A1 - Steiger, Thomas A1 - Kipphardt, Heinrich A1 - Matschat, Ralf T1 - International comparability of determination of mass fractions of chromium, copper, iron, manganese and zinc in aluminium alloy: Comité consultatif pour la quantité de matière key comparison K42 N2 - The degree of equivalence within the participating national metrology institutes for the measurement results of the mass fractions of the analytes Cr, Cu, Fe, Mn and Zn in an aluminium alloy was assessed. This interlaboratory comité consultatif pour la quantité de matière key comparison (CCQM-K42) was organised as an activity of the Inorganic Analytical Working Group of CCQM. In total seven laboratories participated, six of them for all analytes. Measurands were the mass fractions of the analytes in a range of 0.05 and 0.2%. As an outcome the consistency of the results for all elements investigated was acceptable, hence satisfactory comparability was established. An aluminium based certified reference material—undisclosed to the analysts which one it was—was used as test sample. For the purpose of this study homogeneity was tested at BAM. Each laboratory was free to choose any analytical method they wanted to use for the analysis. Consequently various methods of measurement were employed: instrumental neutron activation analysis, X-ray fluorescence spectrometry (XRF) using fused cast-bead method combined with reconstitution technique, inductively coupled plasma optical emission spectrometry (ICP OES) and inductively coupled plasma mass spectrometry. Metrological traceability of the measurement results to the SI unit had to be demonstrated. Therefore, methods such as spark OES or XRF (without fused cast-bead technique)—both of them being most important methods for the analysis of metals and alloys in industrial laboratories—could not be used in the frame of the key comparison. KW - Aluminium alloy KW - International comparison KW - CCQM-K42 KW - Key comparison PY - 2010 DO - https://doi.org/10.1007/s00769-010-0641-5 SN - 0949-1775 SN - 1432-0517 VL - 15 IS - 7 SP - 401 EP - 407 PB - Springer CY - Berlin AN - OPUS4-21628 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abad Andrade, Carlos Enrique A1 - Florek, S. A1 - Becker-Ross, H. A1 - Huang, M.-D. A1 - Heinrich, Hans-Joachim A1 - Recknagel, Sebastian A1 - Vogl, Jochen A1 - Jakubowski, Norbert A1 - Panne, Ulrich T1 - Determination of boron isotope ratios by high-resolution continuum source molecular absorption spectrometry using graphite furnace vaporizers N2 - Boron isotope amount ratios n(10B)/n(11B) have been determined by monitoring the absorption spectrum of boron monohydride (BH) in a graphite furnace using high-resolution continuum source molecular absorption spectrometry (HR-CS-MAS). Bands (0→0) and (1→1) for the electronic transition X1Σ+ → A1Π were evaluated around wavelengths 433.1 nm and 437.1 nm respectively. Clean and free of memory effect molecular spectra of BH were recorded. In order to eliminate the memory effect of boron, a combination of 2% (v/v) hydrogen gas in argon and 1% trifluoromethane in argon, an acid solution of calcium chloride and mannitol as chemical modifiers was used. Partial least square regression (PLS) for analysis of samples and reference materials were applied. For this, a spectral library with different isotopes ratios for PLS regression was built. Results obtained around the 433.1 nm and 437.1 nm spectral regions are metrologically compatible with those reported by mass spectrometric methods. Moreover, for the evaluated region of 437 nm, an accuracy of 0.15‰ is obtained as the average deviation from the isotope reference materials. Expanded uncertainties with a coverage factor of k = 2 range between 0.15 and 0.44‰. This accuracy and precision are compatible with those obtained by mass spectrometry for boron isotope ratio measurements. KW - Boron isotopes KW - Isotope ratios KW - Boron monohydride KW - Molecular absorption KW - High-resolution continuum source absorption spectrometry KW - Graphite furnace KW - Memory effect KW - HR-CS-MAS PY - 2017 UR - http://www.sciencedirect.com/science/article/pii/S0584854717302537 DO - https://doi.org/10.1016/j.sab.2017.08.012 SN - 0584-8547 VL - 136 SP - 116 EP - 122 PB - Elsevier CY - Amsterdam, The Netherlands AN - OPUS4-42071 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wienold, Julia A1 - Traub, Heike A1 - Bresch, Harald A1 - Seeger, Stefan A1 - Recknagel, Sebastian A1 - Kipphardt, Heinrich T1 - Effort on calibration of infrared spark ablation of copper with synthetic copper standards N2 - Two types of copper samples, compact certified copper reference materials and calibration samples prepared from liquid doped, pressed copper powders, were studied in terms of accuracy of obtained calibration functions originating from infrared spark ablation. Additionally, corresponding particle size distributions of the aerosols from infrared spark ablation were recorded. It is shown that the differences in quantification results, originating from the two sets of calibration functions, could not mainly be ascribed to different particle size distributions of the two copper sample types. Possible other causes, as different ablation rates, parts of melting and differences of the chemical constitutions of the two sample types were explored. KW - Calibration KW - Spark ablation KW - Synthetic standard KW - Particle size distribution KW - Fractionation KW - Laser ablation KW - ICP-MS PY - 2011 DO - https://doi.org/10.1016/j.sab.2011.04.005 SN - 0584-8547 SN - 0038-6987 VL - 66 IS - 6 SP - 432 EP - 438 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-24065 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wienold, Julia A1 - Traub, Heike A1 - Lange, Britta A1 - Giray, Thorsten A1 - Recknagel, Sebastian A1 - Kipphardt, Heinrich A1 - Matschat, Ralf A1 - Panne, Ulrich T1 - Elemental analysis of copper and magnesium alloy samples using IR-laser ablation in comparison with spark and glow discharge methods N2 - Three methods for direct solid sampling of bulk material namely IR laser ablation, glow discharge and spark OES, were compared with respect to analytical figures of merit obtained for elemental analysis with atomic spectrometry. Matrices investigated were copper, pressed doped copper powder, and magnesium alloys. For the vast majority of analytes, statistical equivalence regarding precision (usually ≤ 5%) and the performance of the calibrations between the compared methods was demonstrated. KW - LA-ICP-MS KW - GD-MS KW - Spark-OES KW - LA-ICP-OES KW - Copper KW - Magnesium PY - 2009 DO - https://doi.org/10.1039/b903251g SN - 0267-9477 SN - 1364-5544 VL - 24 SP - 1570 EP - 1574 PB - Royal Society of Chemistry CY - London AN - OPUS4-20257 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Recknagel, Sebastian A1 - Kipphardt, Heinrich A1 - Panne, Ulrich T1 - Certified reference materials: CRM - ERM - EURONORM T2 - Reference Materials and Interlaboratory Comparisons II CY - Medlov, Czech Republic DA - 2005-11-07 KW - CRM KW - ERM KW - ECRM PY - 2005 SN - 80-86380-30-0 SP - 7 EP - 12 PB - Cesky metrologicky institut CY - Medlov AN - OPUS4-11253 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abad Andrade, Carlos Enrique A1 - Florek, S. A1 - Becker-Ross, H. A1 - Huang, M.-D. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin A1 - Lippitz, Andreas A1 - Hodoroaba, Vasile-Dan A1 - Schmid, Thomas A1 - Heinrich, Hans-Joachim A1 - Recknagel, Sebastian A1 - Jakubowski, Norbert A1 - Panne, Ulrich T1 - Zirconium permanent modifiers for graphite furnaces used in absorption spectrometry: understanding their structure and mechanism of action N2 - The mechanism of action of zirconium permanent modifiers on graphite surfaces was investigated in order to understand its influence on the analytical signal in atomic and molecular absorption spectrometry (AAS/MAS). For this, the molecule formation of CaF was studied, which is used for the indirect analytical determination of fluorine in high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS-GFMAS). The kinetics of this reaction was established by monitoring its molecular spectrum at different atomisation temperatures. An Arrhenius plot showed a pseudo-first order reaction with respect to fluorine (n = 1). An intermediate state was isolated, and its structure was elucidated by spectroscopic methods: scanning electron microscopy with energy dispersive X-ray spectroscopy (SEMEDX), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XANES and EXAFS), and Raman microspectroscopy. We propose here a mechanism, where ZrO2 acts as a heterogeneous catalyst: after a pyrolytic step, an intermediate state of ZrO(OCaF) is activated, and at higher temperatures, CaF(g) is released from the zirconium-coated graphite surface. No evidence of the formation of zirconium carbide was found. Consequently, as the CaF formation is catalysed by a heterogeneous catalyst, surface modifications with ZrO2 nanoparticles and ZrO xerogels were investigated in order to increase the surface area. Their influence was evaluated in the molecule formation of CaF, CaCl, CaBr, and CaI. Graphite furnace modification with zirconium oxide nanoparticles proves to be the best choice for fluorine analysis with a signal enhancement of more than eleven times with respect a non-coated graphite furnace. However, the influence of zirconium modifications in the analytical signals of Cl, and I is lower than the F signals or even negative in case of the Br. Understanding zirconium modifiers as heterogeneous catalysts offers a new perspective to AAS and MAS, and reveals the potential of surface analytical methods for development of improved permanent modifiers and graphite furnace coatings. KW - Zirconium KW - HR-CS-MAS KW - Graphite furnace KW - Nanoparticles KW - Xerogel KW - Calcium monofluoride KW - Absorption spectrometry PY - 2018 UR - https://pubs.rsc.org/en/content/articlelanding/2018/ja/c8ja00190a DO - https://doi.org/10.1039/C8JA00190A SN - 0267-9477 VL - 33 IS - 12 SP - 2034 EP - 2042 PB - Royal Society of Chemistry AN - OPUS4-46775 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -