TY - CONF A1 - Bayat, Mehmet E. A1 - Huber, C. A1 - Kipphardt, Heinrich A1 - Tiebe, Carlo A1 - Engelhard, Carsten T1 - Towards a sensor-based methodology to determine online calorific values of H2-enriched natural gases in the grid N2 - The German National Hydrogen Strategy (NWS) envisions a transition towards a hydrogen-based energy grid. However, due to the material incompatibility of existing pipeline infrastructure for amounts of hydrogen higher than 10 cmol/mol, many system components of the existing grid must be replaced with significant costs and considerable time investments. Given these constraints, the admixture of hydrogen into natural gas (NG) to create a hydrogen-enriched NG blend has been designated as a transitional technology. The NWS supports this approach on a regional and time-limited basis, but clearly states that it is not intended as a permanent solution. Nevertheless, the conversion to a fully hydrogen-based grid is expected to take several decades. During this transitional phase, precise process analytical monitoring of hydrogen amounts in the NG blend is essential to ensure both energy efficiency via calorific value control and operational safety. These procedures require cost-effective, robust, and reliable sensor technologies capable of real-time, in situ/on-site quantification of hydrogen amounts in NG. In response to this need, we have advanced a physical sensing approach utilizing an oscillating cantilever in collaboration with Truedyne Sensor AG. This sensor system enables quantification of hydrogen amounts, direct calorific value determination as well as display of beneficial gas properties, like density, viscosity, and thermal conductivity. Moreover, the enhanced cantilever system enables direct physical sensing and can also be operated in a quasi-binary mode. We performed comparative evaluations against two benchmark sensor systems to validate the developed technology. One utilizes chemical sensing, and the other operates on thermal conductivity measurements for hydrogen quantification. Through standardized testing, we demonstrated that the cantilever-based sensor offers both high effectiveness and competitive performance compared to current state-of-the-art technologies for accurate hydrogen detection in natural gas and precise determination of its calorific value. T2 - Gas Analysis 2026 CY - Paris, France DA - 27.01.2026 KW - Hydrogen KW - Natural Gas KW - Sensor KW - Calorific Value KW - Grid PY - 2026 AN - OPUS4-65505 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bayat, Mehmet Emin A1 - Kipphardt, Heinrich A1 - Tiebe, Carlo A1 - Tuma, Dirk A1 - Engelhard, Carsten T1 - Trace-Level Ammonia–Water Interactions in Hydrogen: Challenges in Gas Purity Analysis Using Optical-Feedback Cavity-Enhanced Absorption Spectroscopy (OF-CEAS) N2 - Ammonia is a critical impurity in hydrogen fuel due to its irreversible poisoning effect on proton exchange membrane fuel cells. Therefore, international standards (e.g., ISO 14687) set a stringent threshold of 100 nmol/mol. Furthermore, with the growing potential use of ammonia as a hydrogen carrier, its accurate quantification is becoming increasingly important. However, the presence of trace humidity poses analytical challenges, as ammonia may interact with water or interfaces, thereby affecting its detectability. Therefore, the goal of this work is to enable accurate trace ammonia quantification for hydrogen purity measurements through fundamental studies of the methodological challenges. Here, low-pressure sampling (ultra)long-path Optical-Feedback Cavity-Enhanced Absorption Spectroscopy (OF-CEAS) was applied with an effective optical path length of approximately 6.17 km. We studied three average amounts of ammonia: (38.2 ± 0.8) nmol/mol, (74.8 ± 0.7) nmol/mol, and (112.1 ± 1.2) nmol/mol. Furthermore, these amounts were investigated at trace-humidity levels ranging from 0.8 to 8.5 ppmV. We observed a systematic, nonlinear, and humidity-dependent positive measurement bias of up to + (1.0 ± 0.2) nmol/mol at the maximum investigated trace-humidity volume fraction of 8.5 ppmV. This bias was not caused by spectral interference but rather by water-induced accumulation of ammonia within the optical cavity. Moreover, time-resolved measurements in the presence of trace ammonia showed that water desorption follows first-order kinetics, whereas water adsorption followed mixed-order kinetics with an apparent reaction order of 1.57 ± 0.03. Distinct hydration states of surface-bound ammonia were identified, whereas under dry conditions and with increasing amounts of ammonia, enhanced surface adhesion through intermolecular clustering was observed. In addition, the presence of ammonium species within the sorption layer was indirectly confirmed by our experiments. In conclusion, we provide a deeper insight into trace-level ammonia–water interactions and establish a framework for optimizing methodologies, particularly for (ultra)long-path optical gas measurement systems. KW - Ammonia KW - Hydrogen KW - OF-CEAS KW - Humidity KW - Surface Interactions KW - Adsorption PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643627 DO - https://doi.org/10.1021/acsmeasuresciau.5c00105 SN - 2694-250X SP - 1 EP - 15 PB - American Chemical Society (ACS) AN - OPUS4-64362 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bayat, Mehmet A1 - Kipphardt, Heinrich A1 - Tiebe, Carlo A1 - Engelhard, Carsten T1 - Effect of Trace Humidity on Trace Ammonia Quantification N2 - Hydrogen is receiving growing attention as a promising medium for energy storage and transportation. Proton exchange membrane (PEM) fuel cells are a key technology for energy conversion from hydrogen. However, high purity hydrogen is required for this technology, as described in standards such as ISO 14687:2019. A critical impurity that impairs PEM efficiency is ammonia, for which a limit value of 100 nmol/mol applies. In addition, the maximum amount of humidity is specified with 5 µmol/mol. The presence of humidity in hydrogen at levels up to 50 times higher than ammonia raises the critical question of whether ammonia can still be quantified accurately in the lower nmol/mol range without interference from water. In addition, the general question arises as to whether the critical analyte, ammonia, can still be detected at all, given the expected surface effects at such amounts of trace humidity. In this work, we describe the influence of trace humidity on the surface behavior of adsorbed ammonia on stainless steel. Samples with ammonia at approximately 100 nmol/mol in hydrogen, with trace humidity levels ranging from 3 µmol/mol to 10 µmol/mol, were carefully prepared using dynamic mixing. Humidification was conducted using an advanced saturation method. These samples were investigated under atmospheric conditions using low pressure sampling Optical Feedback Cavity Enhanced Absorption Spectroscopy (OFCEAS). From the observed time-dependent signals, kinetics were determined and analyzed, yielding insights on the strength of the adsorption behavior of the analytes. T2 - ANAKON 2025 CY - Leipzig, Germany DA - 10.03.2025 KW - OF-CEAS KW - Hydrogen KW - Ammonia KW - Water KW - Humidity KW - Kinetics KW - Adsorption PY - 2025 UR - https://veranstaltungen.gdch.de/microsite/index.cfm?l=11713&sp_id=2&selSiteID=vplanner AN - OPUS4-64046 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bernardino, Carolina T1 - Effortless Antimicrobial Shield: Spray-coated Silica Nanoparticles For Safer High-touch Surfaces N2 - Functional films with tailored interfacial properties play a pivotal role for the development of next generation surface coatings, particularly in healthcare-related environments. In this contribution, we present a facile spray-coating method for the creation of antimicrobial thin films on high-touch surfaces using mesoporous silica nanoparticles (MSNs) that were specifically functionalized to enable strong adhesion and sustained release of metal-based antimicrobial agents. The process is scalable and addresses key challenges in adhesion control, film homogeneity, and long-term antimicrobial function against a large range of key pathogens responsible for nosocomial infections. Three distinct types of MSNs – bearing amine (MSN-NH₂), carboxy (MSN-COOH), and thiol (MSN-SH) surface groups – were synthesized to optimize both metal ion loading and interactions with polyelectrolyte-based adhesion layers. These surface modifications not only provide chemical handles for Cu²⁺ and Ag⁺ ion coordination but also modulate nanoparticle-substrate interactions and dispersion behavior during film formation. The coating architecture consists of a two-step process: first, spray deposition of polyelectrolyte primers that anchor strongly to stainless steel substrates; second, a nanoparticle layer that bonds electrostatically and chemically to the primer, forming robust films with great surface coverage. The films were characterized to assess structural integrity, adhesion, and functional performance. Transmission electron microscopy (TEM) and N₂ sorption analysis confirmed the mesoporous structure. ATR-FTIR and zeta potential measurements validated surface functionalization and colloidal stability. Environmental SEM revealed conformal coating across the stainless-steel surfaces with uniform nanoparticle distribution. The coating's adhesion strength was maintained through mechanical wiping and simulated wear and abrasion tests, demonstrating film durability relevant in real-world use scenarios. Antimicrobial testing under semi-dry, application-relevant conditions showed excellent performance for Ag⁺-loaded MSN-SH films, inhibiting growth of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. These results highlight the synergistic role of surface chemistry, metal ion loading, and film-substrate adhesion in creating effective and wear-resistant functional coatings. Moreover, these films do not show any cytotoxic properties towards Human Dermal Fibroblasts (HDF). This study contributes new insights into the design of multifunctional films where adhesion, surface functionality, and scalable processing are co-optimized for enhanced performance and shows how combining tailored surface chemistry and wide-ranging antimicrobial activity brings together smart material design for practical and safe use. T2 - MRS Fall Meeting 2025 CY - Boston, MA, USA DA - 30.11.2025 KW - Mesoporous silica nanoparticles KW - Silver KW - Antimicrobial KW - Coatings KW - Thin film PY - 2025 AN - OPUS4-65150 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Braun, Jennifer A1 - Engelhard, Carsten A1 - Kaul, Peter T1 - Optimized fast gas chromatography coupled with proton-transfer-reaction time-of-flight mass spectrometry for the selective near real-time analysis of herbivore-induced plant volatiles N2 - The analysis of herbivore-induced plant volatiles (HIPVs) is essential for understanding plant-environment interactions and defense strategies against herbivores. Proton transfer reaction time-of-flight mass spectrometry (PTR–TOF–MS) is a powerful analytical tool that enables real-time monitoring and quantification of diverse groups of HIPVs. However, the PTR–TOF–MS technique is constrained in its ability to effectively differentiate between isomers. When analyzing complex mixtures of HIPVs, the separation of isomers becomes crucial as major compound classes such as terpenes comprise thousands of isomers. In this study, we present an optimized fast gas chromatography (fastGC) based on a modified version of the commercially available fastGC add-on integrated into a mobile PTR–TOF. The system was optimized for the analysis of emissions from enclosed trunks of Acer platanoides infested by Anoplophora glabripennis (Motschulsky), commonly known as Asian longhorned beetle (ALB). The development of fastGC was primarily focused on the sesquiterpenes α-longipinene, cyclosativene and α-copaene, which serve as strong indicators of ALB infestation. These sesquiterpenes were separated in less than three minutes, with intra-day retention time RSD < 0.6 % and resolutions of 2.6 ± 0.3 and 1.3 ± 0.2. In comparison to the original system, the optimized fastGC demonstrates more than tripled sesquiterpene resolution, twice the sensitivity relative to direct inlet mode, and an approximately 10 % reduction in total analysis time. The optimized fastGC–PTR–TOF allows for near real-time analysis of complex mixtures of biogenic VOCs, making it a powerful tool for environmental monitoring, integrated pest management, and forest protection. KW - Mass Spectrometry KW - PTR-TOF-MS KW - Gas Chromatography KW - Herbivore-induced plant volatiles KW - Sesquiterpenes PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639513 DO - https://doi.org/10.1016/j.chroma.2025.466236 SN - 0021-9673 VL - 1759 SP - 1 EP - 16 PB - Elsevier B.V. AN - OPUS4-63951 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bresch, Harald T1 - Anwendungen von maschinellem Lernen und KI an der BAM N2 - Im Austausch mit den anderen Bundesoberbehörden wurden die KI-Ansätze der verschiedenen Bundesoberbehörden zu spezifischen Themen der Nanowissenschaften präsentiert. Der Vortrag der BAM fokusiert sich auf die Themen "Self driving lab", semantische Segmentierung und Auswertung von elektronenmikroskopischen Bildern sowie die Generierung von ausführbaren Machineninstruktionen aus natürlicher Sprache. Abschließend wird der neue BAM DataStore vorgestellt. T2 - Nano-Behördenklausur 2024 CY - Berlin, Germany DA - 03.07.02024 KW - Nano KW - Bundesoberbehörden KW - Künstliche Intelligenz KW - Neuronale Netzwerke KW - Elektronisches Laborbuch PY - 2024 AN - OPUS4-61819 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chan, George C.-Y. A1 - Engelhard, Carsten A1 - Wiley, Joshua S. A1 - Shoulds, Ayanna U. A1 - Cooks, R. Graham A1 - Hieftje, Gary M. A1 - Shelley, Jacob T. T1 - Characterization of a Low-Temperature Plasma (LTP) Ambient Ionization Source Using Temporally Resolved Monochromatic Imaging Spectrometry N2 - The low-temperature plasma (LTP) probe is a common plasma-based source used for ambient desorption–ionization mass spectrometry (MS). While the LTP probe has been characterized in detail with MS, relatively few studies have used optical spectroscopy. In this paper, two-dimensional (2D) imaging at selected wavelengths is used to visualize important species in the LTP plasma jet. First, 2D steady-state images of the LTP plume for N2+ (391.2 nm), He I (706.5 nm), and N2 (337.1 nm) emissions were recorded under selected plasma conditions. Second, time-resolved 2D emission maps of radiative species in the LTP plasma jet were recorded through the use of a 200 ns detection gate and varying gate delays with respect to the LTP trigger pulse. Emission from He I, N2+, and N2 in the plasma jet region was found to show a transient behavior (often referred to as plasma bullets) lasting only a few microseconds. The N2+ and He I maps were highly correlated in spatial and temporal structure. Further, emission from N2 showed two maxima in time, one before and one after the maximum emission for N2+ and He I, due to an initial electronic excitation wave and ion–electron recombination, respectively. Third, the interaction of the LTP probe with a sample substrate and an electrically grounded metallic needle was studied. Emission from a fluorophore on the sample substrate showed an initial photon-induced excitation from plasma-generated photons followed by electronic excitation by other plasma species. The presence of a grounded needle near the plasma jet significantly extended the plasma jet lifetime and also generated a long-lived corona discharge on the needle. The effect of LTP operating parameters on emission spectra was correlated with mass-spectral results including reagent-ion signals. Lastly, five movies provide a side-by-side comparison of the temporal behavior of emitting species and insights into the interactions of the emission clouds with a sample surface as well as an external needle. Temporally and spatially resolved imaging provided insights into important processes in the LTP plasma jet, which will help improve analyte ion sampling in LTP–MS. KW - Optical spectroscopy KW - Low-temperature plasma KW - Ambient ionization KW - Instrumentation PY - 2023 DO - https://doi.org/10.1177/00037028231184501 VL - 77 IS - 8 SP - 940 EP - 956 PB - SAGE Publications AN - OPUS4-61269 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chan, George C.-Y. A1 - Hieftje, Gary M. A1 - Omenetto, Nicoló A1 - Axner, Ove A1 - Bengtson, Arne A1 - Bings, Nicolas H. A1 - Blades, Michael W. A1 - Bogaerts, Annemie A1 - Bolshov, Mikhail A. A1 - Broekaert, José A.C. A1 - Chan, WingTat A1 - Costa-Fernández, José M. A1 - Crouch, Stanley R. A1 - De Giacomo, Alessandro A1 - D’Ulivo, Alessandro A1 - Engelhard, Carsten A1 - Falk, Heinz A1 - Farnsworth, Paul B. A1 - Florek, Stefan A1 - Gamez, Gerardo A1 - Gornushkin, Igor B. A1 - Günther, Detlef A1 - Hahn, David W. A1 - Hang, Wei A1 - Hoffmann, Volker A1 - Jakubowski, Norbert A1 - Karanassios, Vassili A1 - Koppenaal, David W. A1 - Kenneth Marcus, R. A1 - Noll, Reinhard A1 - Olesik, John W. A1 - Palleschi, Vincenzo A1 - Panne, Ulrich A1 - Pisonero, Jorge A1 - Ray, Steven J. A1 - Resano, Martín A1 - Russo, Richard E. A1 - Scheeline, Alexander A1 - Smith, Benjamin W. A1 - Sturgeon, Ralph E. A1 - Todolí, José-Luis A1 - Tognoni, Elisabetta A1 - Vanhaecke, Frank A1 - Webb, Michael R. A1 - Winefordner, James D. A1 - Yang, Lu A1 - Yu, Jin A1 - Zhang, Zhanxia T1 - Landmark Publications in Analytical Atomic Spectrometry: Fundamentals and Instrumentation Development N2 - The almost-two-centuries history of spectrochemical analysis has generated a body of literature so vast that it has become nearly intractable for experts, much less for those wishing to enter the field. Authoritative, focused reviews help to address this problem but become so granular that the overall directions of the field are lost. This broader perspective can be provided partially by general overviews but then the thinking, experimental details, theoretical underpinnings and instrumental innovations of the original work must be sacrificed. In the present compilation, this dilemma is overcome by assembling the most impactful publications in the area of analytical atomic spectrometry. Each entry was proposed by at least one current expert in the field and supported by a narrative that justifies its inclusion. The entries were then assembled into a coherent sequence and returned to contributors for a round-robin review. KW - Analytical atomic spectrometry KW - Spectroscopy KW - Instrumental analysis PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621588 DO - https://doi.org/10.1177/00037028241263567 SN - 1943-3530 VL - 78 SP - 1 EP - 456 PB - Sage CY - London AN - OPUS4-62158 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chen, Xinyue A1 - Dong, Ximan A1 - Zhang, Chuyan A1 - Zhu, Meng A1 - Ahmed, Essraa A1 - Krishnamurthy, Giridharan A1 - Rouzbahani, Rozita A1 - Pobedinskas, Paulius A1 - Gauquelin, Nicolas A1 - Jannis, Daen A1 - Kaur, Kawaljit A1 - Hafez, Aly Mohamed Elsayed A1 - Thiel, Felix A1 - Bornemann, Rainer A1 - Engelhard, Carsten A1 - Schönherr, Holger A1 - Verbeeck, Johan A1 - Haenen, Ken A1 - Jiang, Xin A1 - Yang, Nianjun T1 - Interlayer Affected Diamond Electrochemistry N2 - Diamond electrochemistry is primarily influenced by quantities of sp3‐carbon, surface terminations, and crystalline structure. In this work, a new dimension is introduced by investigating the effect of using substrate‐interlayers for diamond growth. Boron and nitrogen co‐doped nanocrystalline diamond (BNDD) films are grown on Si substrate without and with Ti and Ta as interlayers, named BNDD/Si, BNDD/Ti/Si, and BNDD/Ta/Ti/Si, respectively. After detailed characterization using microscopies, spectroscopies, electrochemical techniques, and density functional theory simulations, the relationship of composition, interfacial structure, charge transport, and electrochemical properties of the interface between diamond and metal is investigated. The BNDD/Ta/Ti/Si electrodes exhibit faster electron transfer processes than the other two diamond electrodes. The interlayer thus determines the intrinsic activity and reaction kinetics. The reduction in their barrier widths can be attributed to the formation of TaC, which facilitates carrier tunneling, and simultaneously increases the concentration of electrically active defects. As a case study, the BNDD/Ta/Ti/Si electrode is further employed to assemble a redox‐electrolyte‐based supercapacitor device with enhanced performance. In summary, the study not only sheds light on the intricate relationship between interlayer composition, charge transfer, and electrochemical performance but also demonstrates the potential of tailored interlayer design to unlock new capabilities in diamond‐based electrochemical devices. KW - Nanocrystalline diamond KW - Interfaces KW - Electrochemistry KW - TOF-SIMS KW - SEM PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621576 DO - https://doi.org/10.1002/smtd.202301774 SN - 2366-9608 VL - 9 IS - 2 SP - 1 EP - 10 PB - Wiley VHC-Verlag CY - Weinheim AN - OPUS4-62157 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Duarte Bernardino, Carolina T1 - Metal-Ion Loaded Silica Nanoparticles as Antimicrobial Coatings for Safer High-Touch Surfaces N2 - Not only since the Covid-19 pandemic have researchers focused their efforts on high touch surfaces to minimize the contraction of infectious diseases due to human contact. To help prevent the spread of infectious pathogens, surfaces and coatings are designed to minimize the presence or survivability of pathogens on surfaces in various settings, including healthcare centers, long-term care facilities, public transport, schools, and businesses. Extensive research has focused on finding solutions to prevent bacterial transmission and biofilm formation by killing or reducing the attachment of microbes. These solutions include surface-bound active antimicrobials, biocidal coatings, and passive pathogen-repellent surfaces, developed using nanomaterials, chemical modifications, and micro- and nano-structuring. Nanomaterials are a prime candidate for such a solution. Here, we developed mesoporous silica nanoparticles (MSNs) loaded with antimicrobially active silver and copper ions that can be used in sprayable formulations as surface coatings. The influence of different surface functionalization and metal ion loadings on the efficacy of these sprayable coatings was studied. Amine- (MSN-NH2), carboxy- (MSN-COOH) and thiol-functionalized mesoporous silica nanoparticles (MSN-SH) were synthesized and characterized using different techniques, such as transmission electron microscopy (TEM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), dynamic light scattering (DLS), electrophoretic light scattering (Zeta potential measurements) and nitrogen sorption measurements. After loading MSNs with antimicrobially active silver or copper ions, the nanoparticle dispersions were spray-coated on stainless steel substrates that were primed with sprayable polyelectrolyte solutions to enhance coating homogeneity and nanoparticle adhesion. The metal ion release was analyzed by Inductively coupled plasma optical emission spectroscopy (ICP-OES). The antimicrobial properties of the nanoparticle suspension and the coatings were tested against three commonly found pathogenic bacteria, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli as well as a fungal pathogen, Candida albicans. The toxicity of the coatings against human skin cells was also assessed. T2 - STOP Antimicrobial Coatings Conference CY - Mons, Belgium DA - 05.12.2024 KW - Mesoporous Silica Nanoparticles KW - Antimicrobial Coatings KW - Spray-Coating KW - Pathogens PY - 2024 AN - OPUS4-62180 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -