TY - CONF A1 - Resch-Genger, Ute T1 - Reliable measurements of the photoluminescence quantum yield of transparent and scattering luminophores N2 - Optical measurements of transparent solutions of organic dyes and semiconductor quantum dots and scattering materials such as luminescent nanocomposites and microparticles and phosphors dispersed in liquid and solid matrices play an important role in energy conversion, solid-state lighting, medical diagnostics, and security barcoding. A key performance parameter is the photoluminescence quantum yield QY, i.e., the number of emitted per number of absorbed photons. QY of transparent luminophore solutions can be obtained relative to a fluorescence QY standard of known QY.[1] Meanwhile, a first set of certified fluorescence QY standards is available.[2] Such relative QY measurements require a calibrated spectrofluorometer.[1,3] For determining QY of scattering liquid and solid samples, absolute measurements of QY with a calibrated integrating sphere setup are mandatory.[1,4,5] However, scattering QY standards are not available and uncertainties of such measurements have not yet been assessed in interlaboratory comparisons (ILCs). To determine typical sources of uncertainty of absolute QY measurements, we assessed the influence of the measurement geometry and the optical properties of the blank for determining the number of incident photons absorbed by the sample in an ILC using commercial integrating sphere setups and a custom-designed integrating sphere setup. Samples examined included transparent and scattering dye solutions, solid phosphors such as YAG:Ce optoceramics used as LED converter material, and polymer films stained with different amounts of phosphor microparticles. Matching QY values could be obtained for transparent dye solutions and scattering dispersions with a blank with scattering properties closely matching those of the sample, while QY measurements of optoceramic samples with different blanks revealed substantial differences of more than 20 %. Based on our data, we recommend non-absorbing blank materials with a high reflectivity (>95 %) such as a 2 mm-thick PTFE target placed on the sample holder as blanks. T2 - eMRS 2025 Fall Meeting CY - Warsaw, Poland DA - 15.09.2025 KW - Quality assurance KW - Fluorescence KW - Nano KW - Particle KW - Advanced material KW - Synthesis KW - Characterization KW - Fluorescence quantum yield KW - Phosphor KW - Absolute KW - Integrating sphere spectroscopy KW - Dye KW - Standardization KW - Reference material KW - Interlaboratory comparison KW - Uncertainty PY - 2025 AN - OPUS4-64184 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Career Options in Public Service N2 - In the following, an overview of possible career options for chemists is presented covering metrology institutes, departmental research institutes of ministries, Federal and state research institutes and options in areas such as Federal or state institutions in charge of occupational safety, the German armed forces, wastewater treatment plants and labs/institutes controlling water quality, and museums. Thereby also examples and personal insights of the daily work routine are provided for some employers. T2 - Career-Workshop ChiÖD CY - Karlsruhe, Germany DA - 02.04.2025 KW - Quality assurance KW - Reference analysis KW - Standardization KW - Metrology KW - Reference products KW - Reference materials KW - Mission PY - 2025 AN - OPUS4-62867 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - From molecular and nanoscale chromophores with UV/VIS/NIR/SWIR luminescence to multi method characterization of surface coatings N2 - An overview of the research activities of division Biophotonics is presented covering examples for photophysical studies of different types of molecular and nanocrystalline luminophores, luminescent particles, and sensor systems in solution, in dispersion, and in the solid state and multi-method charactreization workflow for the characterization of surface-functionalized engineered nanomaterials. In addition, the importance of reliable optical measurements, particularly standardized workflows for the determination of the key performance parameter luminescence quantum yield of transparent and scattering luminescent samples with fluorescence and integrating sphere spectroscopy, and validated methods for quantifying surface functional groups and ligands on nanomaterials is highlighted. Thereby, also ongoing standardization activities are presented as well as certified reference materials and reference materials from division Biophotonics. T2 - Chinese-German Chemical Association - Annual Meeting CY - Berlin, Germany DA - 22.08.2025 KW - Quality assurance KW - Fluorescence KW - Nano KW - Particle KW - Synthesis KW - Quantum yield KW - Characterization KW - Advanced material KW - Surface KW - Lifetime KW - Sensor KW - Oxygen KW - Ph KW - Standardization KW - Fluorescent probe KW - Reference material PY - 2025 AN - OPUS4-64181 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tavernaro, Isabella A1 - Sander, P. C. A1 - Andresen, Elina A1 - Schedler, U. A1 - Resch-Genger, Ute T1 - Expanding the Toolbox of Simple, Cost-Efficient, and Automatable Methods for Quantifying Surface Functional Groups on Nanoparticles� Potentiometric Titration N2 - Measuring surface functional groups (FGs) on nanomaterials (NMs) is essential for designing dispersible and stable NMs with tailored and predictable functionality. FG screening and quantification also plays a critical role for subsequent processing steps, NM long-term stability, quality control of NM production, and risk assessment studies and enables the implementation of sustainable and safe(r)-by-design concepts. This calls for simple and cost-efficient methods for broadly utilized FGs that can be ideally automated to speed up FG screening, monitoring, and quantification. To expand our NM surface analysis toolbox, focusing on simple methods and broadly available, cost-efficient instrumentation, we explored a NM-adapted pH titration method with potentiometric and optical readout for measuring the total number of (de)protonable FGs on representatively chosen commercial and custom-made aminated silica nanoparticles (SiO2 NPs). The accuracy and robustness of our stepwise optimized workflows was assessed by several operators in two laboratories and method validation was done by cross-comparison with two analytical methods relying on different signal generation principles. This included traceable, chemo-selective quantitative nuclear magnetic resonance spectroscopy (qNMR) and thermogravimetric analysis (TGA), providing the amounts of amino silanes released by particle dissolution and the total mass of the surface coatings. A comparison of the potentiometric titration results with the reporter-specific amounts of surface amino FGs determined with the previously automated fluorescamine (Fluram) assay highlights the importance of determining both quantities for surface-functionalized NMs. In the future, combined NM surface analysis with optical assays and pH titration will simplify quality control of NM production processes and stability studies and can yield large data sets for NM grouping that facilitates further developments in regulation and standardization. KW - Quality assurance KW - Fluorescence KW - Nano KW - Particle KW - Synthesis KW - Characterization KW - Advanced material KW - Surface KW - Standardization KW - Reference material KW - Functional group KW - Quantification KW - Coating KW - Automation KW - Potentiometry KW - Method KW - Validation KW - Optical assay KW - Fluram KW - Fluorescamine KW - qNMR KW - Comparison KW - ILC PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642371 DO - https://doi.org/10.1021/acsmeasuresciau.5c00062 SN - 2694-250X SP - 1 EP - 13 PB - American Chemical Society CY - Washington, DC AN - OPUS4-64237 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Quantifying functional groups and coatings on nanoobjects N2 - Engineered nanomaterials (NM) of different size, shape, chemical composition, and surface chemistry are increasingly used for many key technologies of the 21st century and consumer products. This includes polymer and silica or silica-coated nanoparticles (NP) with covalently bound surface groups, semiconductor quantum dots (QD), metal and metal oxide NP, and lanthanide NP with coordinatively or electrostatically bound ligands, as well as surface-coated nanostructures like micellar encapsulated NP. Decisive for most applications of NMs are their specific surface properties, which are largely determined by the chemical nature and amounts of ligands and functional groups (FGs) on the NM surface. The surface chemistry can strongly affect the physicochemical properties of NM, their charge, hydrophilicity/hydrophobicity, reactivity, function, stability, and processability and thereby their impact on human health and environment. Knowledge of NM surface chemistry plays an important role for NM functionality and performance in (bio)applications and the fate, exposure, dissolution, transformation, and accumulation of NM, and thus, the potential risks for human health and the environment. This highlights the importance of reliable, validated, and eventually standardized analytical methods for analyzing and quantifying NM surface chemistry for process and quality control of NM production, safe use of NMs, design of novel NM, and sustainable concepts for NM fabrication.[1-3] In this context, interlaboratory comparisons (ILCs) are needed to assess method reliability and reference materials with known surface chemistries for establishing surface analytical methods and their performance validation.[2,4] Also, to respond to the increasing number of samples to be analyzed, cost-efficient automation concepts for surface analysis are needed that can be realized with affordable and preferably commercial instrumentation.[5] Here, we provide an overview of analytical methods for FG analysis and quantification used by us for quantifying broadly utilized FGs and ligands on different types of NMs with electrochemical titration methods, optical assays, nuclear magnetic resonance (NMR) and vibrational (IR) spectroscopy, and X-ray based and thermal analysis methods.[1,2] Thereby, method- and material-related challenges are addressed, and the importance of multi-method characterization approaches easing method validation by method cross-validation. Special emphasis is dedicated to simple, versatile, and cost-efficient methods such as optical assays and electrochemical titration methods. T2 - eMRS Fall Meeting 2025 CY - Warsaw, Poland DA - 15.09.2025 KW - Quality assurance KW - Fluorescence KW - Nano KW - Particle KW - Synthesis KW - Characterization KW - Advanced material KW - Surface KW - Standardization KW - Reference material KW - Functional group KW - Quantification KW - Coating KW - Interlaboratory comparison KW - Uncertainty PY - 2025 AN - OPUS4-64183 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Güttler, Arne T1 - Certified Reference Materials for the Quantification and Standardization of Fluorescence-based Measurements N2 - The size and shape of photoluminescence signals is affected by wavelength-, polarization-, and time-dependent instrumentspecific contributions and the compound- and environment-specific photoluminescence quantum yield. The former hamper the comparability of fluorescence measurements performed on different measuring devices. The commonly relatively done determination of the performance parameter requires suitable quantum yield standards with well-known. The performance of such measurements is, e.g., described in the written standard IEC 62607 currently revised. T2 - Colloquium für Optische Spektrometrie 2025 CY - Jena, Germany DA - 24.09.2025 KW - Quality assurance KW - Fluorescence KW - Nano KW - Particle KW - Advanced material KW - Calibration KW - Characterization KW - Fluorescence quantum yield KW - Phosphor KW - Absolute KW - Integrating sphere spectroscopy KW - Dye KW - Standardization KW - Reference material KW - Interlaboratory comparison KW - Uncertainty PY - 2025 AN - OPUS4-64213 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Quantifying the total and accessible amount of surface functionalities and ligands on nanomaterials N2 - Engineered nanomaterials (NMs) of various chemical composition and surface functionalization are routinely fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage. NM dispersibility, stability, processability, and function as well as the interaction with biological species and environmental fate are largely determined by NM surface functionalities, i.e., functional groups (FGs) and ligands. Therefore, reliable, reproducible, and eventually standardized surface characterization methods are vital for quality control of NMs, and mandatory to meet increasing concerns regarding their safety. Suitable methods for determining surface functionalities on ligand-stabilized core and core/shell NPs include advanced techniques such as traceable quantitative nuclear magnetic resonance (qNMR) as well as X-ray electron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS), and simpler optical and electrochemical methods.[1] The latter less costly and fast methods, which can be automated, are often used by NM producers for process and quality control.[1,2] To validate methods, establish measurement uncertain-ties, test reference materials, and produce reference data, multi-method characterization studies are needed.[3,4] as well as interlaboratory comparisons (ILC) on determining NM surface chemistry and well characterized test and reference NMs providing benchmark values.[5,6] Here, we present examples for quantifying common surface FGs such as amino and carboxyl groups on functional NMs of different chemical composition such as silica, polymer, iron oxide, and lanthanide-based upconversion nanoparticles with optical assays, electrochemical titration methods, qNMR, and chromatographic separation techniques. In addition, ongoing interlaboratory comparisons will be presented. T2 - Yucomat 2025 CY - Herec Novi, Montenegro DA - 01.09.2025 KW - Quality assurance KW - Fluorescence KW - Nano KW - Particle KW - Synthesis KW - Characterization KW - Advanced material KW - Surface KW - Standardization KW - Reference material KW - Functional group KW - Quantification KW - Coating KW - Interlaboratory comparison KW - Uncertainty PY - 2025 AN - OPUS4-64182 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - The emp project smurfnano – Standardizing the quantification of surface functionalities, ligands, and coatings on nanomaterials N2 - For industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage, meanwhile engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated. NP function, interaction with biological species, and environmental fate are largely determined by surface functionalities. Reliable, reproducible, and standardized surface characterization methods are therefore vital for quality control of NPs, and mandatory to meet increasing concerns regarding their safety. Also, industry, international standardization organizations, regulatory agencies, and policymakers need validated and standardized measurement methods and reference materials. These needs are addressed by the recently started European metrology project SMURFnano involving 12 partners from different National Metrology Institutes, designated institutes, and research institutes, two university groups as well as one large company and one SME producing NPs. This project as well as first results derived from the development of test and reference materials with a well characterized surface chemistry and ongoing interlaboratory comparisons will be presented. T2 - LNE Workshop CY - Paris, France DA - 04.11.2025 KW - Quality assurance KW - Fluorescence KW - Nano KW - Particle KW - Synthesis KW - Characterization KW - Advanced material KW - Surface KW - Standardization KW - Reference material KW - Functional group KW - Quantification KW - Coating KW - Automation KW - Potentiometry KW - Method KW - Validation KW - Optical assay KW - Fluram KW - qNMR KW - Comparison KW - ILC PY - 2025 AN - OPUS4-64725 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - The SMURFnano project - standardized measurements of surface functionalities on nanoparticles N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, optoelectronics, and information storage. NP function, interaction with biological species, and environmental fate are largely determined by surface functionalities. Reliable, reproducible, and standardized surface characterization methods are therefore vital for quality control of NPs, and mandatory to meet increasing concerns regarding their safety. Also, industry, international standardization organizations, regulatory agencies, and policymakers need validated and standardized measurement methods and reference materials. However, methodologies for determining NP surface properties, including the amount, chemical composition, and homogeneity of surface functionalities and coatings are largely non-standardized. Suitable methods for determining surface functionalities on ligand-stabilized core and core/shell NPs include advanced techniques such as traceable quantitative nuclear magnetic resonance (qNMR) as well as X-ray electron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS), and simpler optical and electrochemical methods. The latter less costly methods are often used by SMEs, e.g., for quality control. To validate methods, establish measurement uncertainties, test reference materials, and produce reference data, international interlaboratory comparisons (ILC) on NP surface functionalization measurements are required and well characterized test and reference nanomaterials providing benchmark values.[1] These needs are addressed by the recently started European metrology project SMURFnano involving 12 partners from different National Metrology Institutes, designated institutes, and research institutes, two university groups as well as one large company and one SME producing NPs. This project as well as first results derived from the development of test and reference materials with a well characterized surface chemistry and ongoing interlaboratory comparisons will be presented. T2 - eMRS CY - Strasbourg, France DA - 27.05.2025 KW - Quality assurance KW - Reference analysis KW - Standardization KW - Metrology KW - Reference products KW - Reference materials KW - Mission KW - Surface chemistry KW - Nano KW - Particle KW - qNMR KW - XPS KW - Fluorescence KW - Optical assays KW - Interlaboratory comparison KW - Uncertainty PY - 2025 AN - OPUS4-63243 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brinkmann, A. T1 - A qNMR Method for Quantification of Surface Functional Groups on Silica Nanoparticles: Bilateral Comparisons N2 - Nanomaterials (NM) of different size, shape, morphology, composition, and surface chemistry are used in a wide range of applications, including medical diagnostics, and imaging and consumer products. The importance of an adequate and reliable characterization is crucial for quality control during NM production, for ensuring an optimum function for the desired application, and for risk assessment studies. Currently there is a lack of reliable and validated methods and reference materials for quantifying NM surface functional groups, despite the importance of surface chemistry for the production of colloidally stable materials, further processing steps, and the interaction with the environment and biological species. Following our initial study on the use of qNMR for quantifying the amount of amino groups on surface modified silica (1), we have carried out two bilateral comparisons between NRC and BAM to further develop and optimize a reliable protocol for these measurements (2,3), using aminated silica nanoparticles prepared by multiple methods, both commercial and in-house synthesized, and with varying amine content. Solution qNMR is based on dissolving aminated silica nanoparticles in strong base to release the surface grafted amino silane molecules, followed by the quantification of these molecules by solution qNMR using an internal standard. This method provides the amount of total amino groups present in the sample, which can differ from probe accessible or surface-sensitive measurements performed with X-Ray photoelectron spectroscopy (XPS). Complementary measurements using optical assays, involving a labeling step with a dye reporter, and XPS are employed to assess the probe accessible and surface amine content for representative samples. These measurements, which illustrate the advantages and potential limitations of the different characterization methods, will contribute to establish a basis for testing the protocol in an international inter-laboratory comparison and for standardization at ISO Technical Committee 229 – Nanotechnologies. T2 - BERM CY - Halifax, Canada DA - 01.06.2025 KW - Quality assurance KW - Nano KW - Particle KW - Synthesis KW - Advanced materials KW - Characterization KW - Electron microscopy KW - Silica KW - Surface KW - qNMR KW - Optical assay KW - Interlaboratory comparison KW - Metrology KW - Standardization PY - 2025 AN - OPUS4-63527 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -