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Single-event analysis of discrete entities using microwave-induced nitrogen plasma–mass spectrometry
No full textICP-MS has become a standard for (ultra)trace elemental analysis due to its excellent sensitivity and multi-element capabilities. However, its widespread use is hampered by spectral interferences—especially in the low mass range (<81 amu)—primarily arising from Ar-based polyatomic ions, such as ArO+ and Ar2+, which compromise the accurate quantification of key elements like Fe and Se.1 Over the years, improvements such as collision/reaction cells and sector-field configurations have
helped mitigate these interferences, albeit often at the cost of instrument complexity and increased operational burden.The microwave-induced nitrogen plasma (MINP) source, sustained by microwaves at atmospheric pressure and using nitrogen as the plasma gas, offers a fundamentally different plasma environment. Nitrogen is not only more economical (40-60%) and readily available than Ar, but also avoids the generation of problematic Ar-based interferences. While MINP had been previously applied in optical emission and bulk mass spectrometry,2 its implementation in single-event detection had not yet been demonstrated.
This study pioneers the application of MINP-MS in single-event mode for real-time, high-throughput characterization of NPs, cells, and MPs. The evaluation began with Fe2O3 NPs monitoring the 56Fe nuclide, with a limit of detection of 8.6 ag for Fe, equivalent to a particle size threshold of 19 nm—surpassing the detection capabilities of quadrupole-based ICP-MS systems. Size distribution results
obtained by SP-MINP-MS for Fe2O3 NPs (20–70 nm) matched closely with transmission electron microscopy (TEM) and dynamic light scattering (DLS), confirming the method’s accuracy.
For Se, despite its high ionization energy, metallic SeNPs (150 and 250 nm) were reliably quantified by monitoring 80Se. A calibration curve constructed using SeNP standards yielded excellent linearity (R2 = 0.9994). This approach was further extended to single-cell analysis, using Se-enriched yeast (SELM-1 CRM) as a model. A transport efficiency-independent calibration strategy was employed, relying on SeNPs to determine Se content per cell. The results showed strong agreement with data from conventional SC-ICP-MS, with average Se masses of ~65 fg per cell, validating the
performance of SC-MINP-MS for biological systems. Additionally, the instrument's capability to handle large, low atomic number particles was demonstrated via the analysis of polystyrene (PS) and polytetrafluoroethylene (PTFE) MPs. These MPs (2.5–3.0 µm) were quantified by monitoring 12C+ signals and applying a calibration strategy using citric acid as a standard. The resulting size distributions closely matched nominal sizes, reinforcing the system’s robustness for micrometer-sized polymeric materials. Event durations ranging from 470 to over 900 µs were consistent with literature values for single-entity ICP-MS and correlated well with particle size.
These findings establish single-event MINP-MS as a promising analytical platform for analyzing discrete entities. It provides significant advantages over conventional Ar-based ICP-MS, including reduced interferences, lower operational cost, and comparable or superior sensitivity for analytes such as Fe and Se. By avoiding the limitations of Ar-based plasmas and enabling accurate quantification across a wide range of particle types and sizes, MINP-MS in single-event mode opens new avenues for high-resolution, interference-free elemental analysis at the individual entity level
Nanoparticle Characterisation - The long way to standardisation
No full textDiese Präsentation gibt einen Überblick über die Entwicklung der Nanopartikelforschung von ca. 2005 bis heute. Beginnend mit den Besonderheiten von Nanopartikeln und der Aufnahme in den menschlichen Körper über Messmethoden bis hin zur Entwicklung einer Prüfrichtlinie im Rahmen der OECD und einem Ausblick über die absehbaren digitalen Entwicklungen
XCT-assisted micromechanical modeling of the effect of pores on the plastic deformation and mechanical characteristics of PBF-LB/M-produced copper alloys
No full textDue to the low absorption of fiber laser by copper particles, the laser-based powder bed fusion (PBF-LB/M) processing of copper components is accompanied by the development of different types of porosities within the printed samples. This research aims to assess the consequences of various process-induced pores on the me
chanical characteristics and deformation of PBF-LB/M-produced copper alloys. Several copper alloys were processed using metal-coated particles and varied laser intensities, yielding samples with different types and amounts of porosities. For instance, CuCrZr alloys processed at 325 J/mm³ and 257 J/mm³ had 0.009 % and 1.117 % porosities, dominated by keyhole and lack-of-fusion pores, respectively. Moreover, PBF-LB/M pro cessing of Cr- and Nb-coated CuNi3SiCr particles accompanied by the generation of 0.004 % and 1.861 % porosities within the samples, predominantly featuring metallurgical and oxidation pores, respectively.
Compression and nanoindentation tests revealed that the CuNi3SiCr alloy exhibited superior mechanical properties compared to the CuCrZr sample (nanoindentation hardness values 2.2 GPa and 1.4 GPa, respectively), while the presence of lack-of-fusion pores notably diminished their mechanical performance. X-ray computed tomography (XCT) reconstruction slices and scanning electron microscopy (SEM) images were then used for developing the representative volume elements (RVEs) based micromechanical models. The micromechanical
simulations established a structure-property correlation that can simulate the compressive deformation and mechanical characteristics of PBF-LB/M-produced copper alloys as a function of their incorporated pore characteristics. Due to the closure of the pores at the first stages of deformation, samples with minimal keyhole and metallurgical porosities exhibited homogeneous plastic deformation. On the other side, based on the JohnsonCook model, strain concentration and crack propagation around the lack-of-fusion pores lead to damage initi
ation in the printed samples at a strain level of 5
Circular Economy - Umsetzung: Wer, was, wo, wie?
No full textDer Vortrag gibt komplementär zu der Theorie der Circular Economy und der technischen Umsetzung sowie Forschung einen Überblick über die aktuellen Entwicklungen in der Politik und Normung. Es werden die Schlüssel-Stakeholder und -gremien inkl. ihrer Wirkungsradien und der Schnittstellen miteinander vorgestellt. Des Weiteren erfolgt ein Überblick und Erklärungen zu Webseiten der Europäischen Kommission mit allgemeinen Inhalten zur Rechtslandschaft der Circular Economy und Möglichkeiten der Beteiligung
Biobased and biodegradable polymers - sustainability and circular economy
No full textThe presentation shows recent results on the synthesis and modification of environmentally relevant polymers based on renewable resources and the associated development of robust, high quality analytical methods. The first topic presents analytical results for star-shaped polylactides with different degrees of functionalisation. It is shown how liquid chromatography and mass spectrometry methods complement each other in a proven way to obtain accurate molar masses and to quantify chemically heterogeneous species. The second part presents an approach to incorporate lignin into epoxy matrices to obtain covalently adaptable epoxy networks that can be reprocessed and reused
NICOLHy - 2nd Stakeholder Advisory Board meeting
No full textThe NICOLHy project aims to develop a novel insulation concept based on Vacuum Insulation Panels (VIP) that enables the safe, cost- and energy efficient storage of large quantities of LH2. Such large scale LH2 storage technology is necessary for establishing a hydrogen economy with dimensions between 40.000 m³ and more than 200.000 m³ of LH2. However, new design concepts are needed because the currently available technologies used in small and medium storages today are not suitable for up-scaling. The main problems prohibiting the up-scaling are the long production time due to the process chain, the low failure tolerance and the spherical shape, which reduces the payload in technical applications by up to 50% compared to other shapes. The novel concept will change these conditions by a system which is modular, open-form, time-and cost efficient while production, operation and service, multi-failure tolerant and applicable for onshore and offshore applications. The presentations shows details to the concept and presents several safety concerns the project has to deal with.
This document contains all presentations from NICOLHys second Stakeholder Meeting
Simultaneously Mechanically Flexible, Photobending, and Acidochromic Cyanostilbene Molecular Crystals
No full textMolecular crystals that respond to multiple stimuli are gaining significant attention for their potential in smart materials like actuators and sensors. However, imparting multiple stimuli-responsive properties to a single crystal remains a major challenge. Herein, we report two cyanostilbene derivative-based crystals 1 and 2, with various responses to stimuli such as mechanical stress, light, acid vapors, etc. Both crystals 1 and 2 demonstrated mechanical flexibility and reversible acidochromism. Additionally, crystal 1 also exhibited light-induced photobending, which is ascribed to Z to E photoisomerization. Detailed structure–property correlation was established to unravel distinct mechanical responses. The development of these multitasking crystals may find applications in multitasking actuators, anticounterfeiting materials, and more
Fast crack healing in glass-matrix composites with rigid filler percolation frameworks
No full textTo ensure the durability of solid oxide fuel cell sealants, the understanding of the microstructural influence on viscous crack healing is essential. To this end, the effect of microstructure with respect to the spatial distribution of filler particles on viscous crack healing was studied with confocal laser scanning microscopy in glass-matrix composites (GMCs) made by mix-milling and sintering of sodalime magnesium silicate glass and Φ ≈ 6 vol% ZrO2 chemically inert rigid filler particles. This way, no change in Φ occurred during the crack healing treatments studied on Vickers indentation-induced radial cracks in polished GMC surfaces.
Different microstructures were mimicked using different ZrO2 particle sizes for mix-milling. Unlike coarse ZrO2 particles, similar in size to the glass particle, fine ZrO2 particles, much smaller than the glass particles, form a rigid percolation framework (RPF) of ZrO2 filler particles around the former glass particles or glass particle agglomerates. For this RPF microstructure, crack healing was observed more readily as crack healing retardation phenomena like large-scale crack widening and crack tip rounding were strongly reduced, whereas narrow cracks could still heal locally within the glassy regions
Simulation der Wasserstoffverteilung in UP-geschweißten Grobblechen als Bewertungstool für die Kaltrissanfälligkeit von Offshorestrukturen
No full textGründungsstrukturen für Offshore-Windkraftanlagen bestehen in der Regel aus hochfesten Stahlgrobblechen, die im UP-Verfahren geschweißt werden, durch den u.U. größere Mengen an Wasserstoff eingebracht werden können. Die große Blechdicke führt zudem zu langen Diffusionswegen und einer verlängerten Diffusionszeit für den Wasserstoff. Infolgedessen kann sich der Wasserstoff in Bereichen mit hoher mechanischer Spannung und Dehnung ansammeln und daher zu einer verzögerten Kaltrissbildung führen. Aufgrund der verzögerten Diffusion muss daher eine Mindestwartezeit von bis zu 48 h eingehalten werden, bevor eine zerstörungsfreie Prüfung durchgeführt wird. Darüber hinaus ist die Beurteilung möglicher Kaltrissstellen sehr komplex. Es wurde daher ein numerisches Modell zur Abbildung einer bauteilähnlichen Schweißnahtprüfung entwickelt. Dazu wurde das Temperaturfeld während des Schweißens und der anschließenden Abkühlung experimentell bestimmt und numerisch simuliert. Auf dieser Grundlage wurde Diffusionsmodell zur numerischen Simulation der zeitlich-örtlichen Wasserstoffkonzentration erstellt. Mit diesem Modell wurden zwei Anwendungsfälle simuliert: (1) Veränderung der Wasserstoffverteilung als Funktion des Temperaturzyklus während des Mehrlagenschweißens und (2) für das Wartezeitintervall ≤ 48 h. Ein Vorteil des Diffusionsmodells ist die Simulation einer normierten Konzentration, d.h. zwischen „0“ (kein Wasserstoff) und „1“ (max. Konzentration), die auf experimentell ermittelte Wasserstoffkonzentrationen skaliert werden kann
Facile Spray-Coating of Antimicrobial Silica Nanoparticles for High-Touch Surface Protection
No full textThe rising threat from infectious pathogens poses an ever-growing challenge. Metal-based nanomaterials have gained a great deal of attention as active components in antimicrobial coatings. Here, we report on the development of readily deployable, sprayable antimicrobial surface coatings for high-touch stainless steel surfaces that are ubiquitous in many healthcare facilities to combat the spread of pathogens. We synthesized mesoporous silica nanoparticles (MSNs) with different surface functional groups, namely, amine (MSN-NH2), carboxy (MSN-COOH), and thiol groups (MSN-SH). These were chosen specifically due to their high affinity to copper and silver ions, which were used as antimicrobial payloads and could be incorporated into the mesoporous structure through favorable host−guest interactions, allowing us to find the most favorable combinations to achieve antimicrobial efficacy against various microbes on dry or semidry high-touch surfaces. The antimicrobial MSNs were firmly immobilized on stainless steel through a simple two-step spray-coating process. First, the stainless steel surfaces are primed with sprayable polyelectrolyte solutions acting as adhesion layers, and then, the loaded nanoparticle dispersions are spray-coated on top. The employed polyelectrolytes were selected and functionalized specifically to adhere well to stainless steel substrates while at the same time being complementary to the MSN surface groups to enhance the adhesion, wettability, homogeneity, and stability of the coatings. 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. Especially MSN-SH loaded with silver ions showed excellent antimicrobial efficacy against all tested pathogens under application-relevant, (semi)dry conditions. The findings obtained here facilitate our understanding of the correlation between the surface properties, payloads, and antimicrobial activity and show a new pathway toward simple and easily deployable solutions to combat the spread of pathogens with the help of sprayable antimicrobial surface coatings