Analytische Chemie
Filtern
Erscheinungsjahr
- 2022 (89) (entfernen)
Dokumenttyp
- Posterpräsentation (89) (entfernen)
Referierte Publikation
- nein (89)
Schlagworte
- Fluorescence (6)
- BAMline (5)
- Process Analytical Technology (4)
- X-ray imaging (4)
- Additive manufacturing (3)
- Amperometry (3)
- Benchtop NMR (3)
- Bioinformatics (3)
- Luminescence (3)
- Metrology (3)
Organisationseinheit der BAM
- 1 Analytische Chemie; Referenzmaterialien (38)
- 8 Zerstörungsfreie Prüfung (27)
- 6 Materialchemie (18)
- 1.8 Umweltanalytik (10)
- 8.5 Röntgenbildgebung (10)
- 6.1 Oberflächen- und Dünnschichtanalyse (9)
- 1.1 Anorganische Spurenanalytik (6)
- 1.2 Biophotonik (6)
- 4 Material und Umwelt (6)
- 6.3 Strukturanalytik (6)
- 1.4 Prozessanalytik (5)
- 1.9 Chemische und optische Sensorik (5)
- 8.0 Abteilungsleitung und andere (5)
- 8.1 Sensorik, mess- und prüftechnische Verfahren (5)
- 8.2 Zerstörungsfreie Prüfmethoden für das Bauwesen (5)
- VP Vizepräsident (5)
- VP.1 eScience (5)
- 6.6 Physik und chemische Analytik der Polymere (4)
- 8.4 Akustische und elektromagnetische Verfahren (4)
- 1.6 Anorganische Referenzmaterialien (3)
- 1.7 Organische Spuren- und Lebensmittelanalytik (3)
- 4.2 Material-Mikrobiom Wechselwirkungen (3)
- 1.5 Proteinanalytik (2)
- 1.3 Instrumentelle Analytik (1)
- 3 Gefahrgutumschließungen; Energiespeicher (1)
- 3.5 Sicherheit von Gasspeichern (1)
- 4.1 Biologische Materialschädigung und Referenzorganismen (1)
- 4.3 Schadstofftransfer und Umwelttechnologien (1)
- 4.5 Kunst- und Kulturgutanalyse (1)
- 8.6 Faseroptische Sensorik (1)
Introduction:
With the introduction of accurate deep learning predictors, spectral matching applications might experience a renaissance in tandem mass spectrometry (MS/MS) driven proteomics. Deep learning models, e.g., Prosit, predict complete MS/MS spectra from peptide sequences and give the unprecedented ability to accurately predict mass spectra that may arise from any given proteome. However, the amount of spectral data is enormous when querying large search spaces, e.g., metaproteomes composed of many different species.
Current spectral library search software, such as SpectraST, is not equipped to meet run time and memory constraints imposed by such large MS/MS databases, covering several millions of peptide spectrum predictions.
Methods:
Inspired by the fragment index data structure that had been introduced with MSFragger, we implement an efficient peak matching algorithm for computing spectral similarity between query and library spectra. Mistle (Metaproteomic index and spectral library search engine) uses index partitioning and SIMD (Single instruction, multiple data) intrinsics, which greatly improves speed and memory efficiency for searching large spectral libraries. Mistle is written in C++20 and highly parallelized.
Results:
We demonstrate the efficiency of Mistle on two predicted spectral libraries for the lab-assembled microbial communities 9MM and SIHUMIx. Compared to the spectral library search engine SpectraST, Mistle shows a >10-fold runtime improvement and is also faster than msSLASH, which uses locality-sensitive hashing. Although Mistle is slower than MSFragger, Mistle‘s memory footprint is an order of magnitude smaller. Furthermore, we find evidence that the spectral matching approach to predicted libraries identifies peptides with higher precision. Mistle detects peptides not found by database search via MSFragger and in turn uncovers unnoticed false discoveries among their matches.
Conclusion:
In this study, we show that predicted spectral libraries can enhance peptide identification for metaproteomics. Mistle provides the means to efficiently search large-scale spectral libraries, highlighted for the microbiota 9MM and SIHUMIx.
Ellipsometry enables the investigation of material properties over a broad spectral range. As a fast and non-destructive method, it is widely used in industry for quality assurance. Despite the wide application of ellipsometry and its high industrial relevance there are some material-specific standards and there have been no generally accepted standards dealing with model validation and measurement uncertainties. The first German standard DIN50989-1: 2018 Ellipsometry – Part1: Principles (currently international standard ISO 23131: 2021) marks the beginning of a 6-part standard series for ellipsometry, which was developed under consideration of GUM.
Hybrid optical measurement technique for detection of defects in epitaxially grown 4H-SiC layers
(2022)
Recent developments in power electronics require the use of new wide bandgap compound semiconductors. Silicon carbide (SiC) is one of the most promising materials for power electronics due to its outstanding properties and commercial availability. Some types of defects in the SiC substrates or homoepitaxial SiC layers can affect the performance of electronic devices in a serious manner or make its operation even impossible. Optical methods such as imaging ellipsometry (IE) and white light interference microscopy (WLIM) were applied for fast and non-contact investigation of defects in the epitaxially grown 12 µm 4H-SiC layers on 4H- SiC substrates.
Monitoring programs should generate high-quality data on the concentrations of substances and other pollutants in the aquatic environment to enable reliable risk assessment. Furthermore, the need for comparability over space and time is critical for analysis of trends and evaluation of restoration of natural environment. Additionally, research work and exercises at the European level have highlighted that reliable measurements of estrogenic substances at the PNEC level are still challenging to achieve.
The project EDC-WFD Metrology for monitoring endocrine disrupting compounds under the EU Water Framework Directive aims to develop traceable analytical methods for determining endocrine disrupting compounds and their effects, with a specific focus on three estrogens of the first watch list (17-beta-estradiol (17βE2), 17-alpha-ethinylestradiol (EE2), and estrone (E1)). Estrogens 17-alpha-estradiol (17E2) and estriol (E3) will be included to demonstrate the reliability of the developed methods and to support the requirements of Directive 2013/39/EC, Directive 2009/90/EC and Commission Implementation Decision (EU) 2018/840, hence improving the comparability and compatibility of measurement results within Europe. During the EDC-WFD project four selected effect-based methods (EBM) will be deeply investigated in order to improve their rationale use and their support in water quality assessment. In particular, the EBM sensitivity, specificity and accuracy on reference materials with single or mixture solutions of the five substances at a concentration of EQS values will be explored.
This contribution will present the objectives and methods applied within the EDC-WFD project.
Natural and synthetic estrogens are key endocrine-disrupting chemicals. Despite occurring at ultra-trace levels (below ng L-1), it is believed that they are contributing to an increase in feminized fish and other endocrine disruptive effects, and hence, their inclusion in the Watch list was not unexpected. One of the main sources ofestrogens to surface waters is wastewater effluent. Once in surface waters, they can partition into different compartments, i.e., water and suspended particulate matter. For this reason, there is an urgent need for a methodology to monitor estrogen levels below the environmental quality standards (EQS) set by the Water Framework Directive requirements.
In this study, a precise and accurate gas chromatography-mass spectrometry method (GC-MS/MS) for the analysis of estrone (E1), 17β-estradiol (17β-E2), 17α-estradiol (17α- E2), 17-alpha-ethinylestradiol (EE2), and estriol (E3) in whole water samples with ng L-1 limit of quantification (LOQ) was developed and validated in accordance with CEN/TS 16800:2020 guidelines.
The Federal Institute for Materials Research and Testing (BAM) organised an interlaboratory comparison (ILC) for the characterisation of 87Sr/86Sr isotope ratios in limestone (IAG/CGL ML-3) and Penrhyn slate (IAG OU-6) reference materials by applying the conventional method for 87Sr/86Sr isotope ratios. Samples were sent to thirteen analytical laboratories . Since both samples are powdered, rock materials, dissolution of the sample and Sr isolation via ion exchange chromatography were mandatory. This was done using acid, microwave/acid, bomb/acid digestion or borate fusion and subsequent isolation of Sr by means of commercially available ion exchange resins. In this study, we present and discuss the potential effects that differences between laboratories, and between two instrumental measurement techniques (i.e., MC-ICP-MS and MC-TIMS), may have upon the dispersion of measurement results of the 87Sr/86Sr isotope ratio in the two aforementioned reference materials. We used a statistical mixed effects model to assess the potential effects of both the laboratory and the measurement technique. Consensus values for both materials and associated standard uncertainties {(IAG/CGL ML-3 (0.708245±0.000004) mol/mol; IAG OU-6 (0.729769±0.000008) mol/mol} were estimated by fitting a linear, Gaussian mixed effects model (Pinheiro and Bates 2000) using the R function “lmer” defined in package “lme4”. The statistical results showed that there is no significant effect attributable to differences between instrumental techniques when both materials are considered together, or separately. The p-value of the test of significance of the measurement technique effect is greater than 0.54. For both materials there were statistically significant effects attributable to differences between laboratories when the measurement results for both materials were considered together and separately. This effect is less than 0.00004 in absolute value. However, for neither material did consideration or disregard for such differences induce significant changes in the estimate of the consensus value for the 87Sr/86Sr isotope ratio. Therefore, the effects attributable to differences between instrumental techniques or between laboratories can safely be disregarded when computing the best estimate for the true value of 87Sr/86Sr isotope ratio in these materials, by the community of expert laboratories represented in this study.
Thirteen laboratories participated in an international interlaboratory comparison for the determination of 87Sr/86Sr isotope ratios in four cement reference materials (RM) using the conventional method for 87Sr/86Sr isotope ratios analyses. Sample dissolution and Sr isolation via ion exchange chromatography were required since the cement samples were distributed as powders. Analytical preparation included the use of various digestion methods including mixed mineral acids, microwave/acid, bomb/acid digestion or borate fusion, followed by Sr separation using ion exchange chromatography. In this study, we evaluated whether any statistically significant differences were attributable to instrumental differences (i.e., MC-ICP-MS and MC-TIMS), or to laboratory-specific techniques (different sample preparation techniques, Sr isolation and the procedures for correcting the data outputs). To evaluate these effects, consensus values for cement RMs and associated standard uncertainties were estimated by fitting a linear, Gaussian mixed effects model using the R function “lmer” defined in package “lme4”. No statistically significant effects (SSE) attributable to instrumental differences regardless of whether the materials are considered together or separately were evident. There were SSE attributable to differences between laboratories for three cement RMs when the individual cements were considered separately. Since consideration or disregard for such differences does not induce significant changes in the estimate of the consensus values for the 87Sr/86Sr isotope ratios in cement RMs, these effects can safely be neglected when calculating the best estimates for the true values of 87Sr/86Sr isotope ratios in these RMs.
Soil acts as a final sink for pollutants. Microplastics from different sources such as plastic mulching, littering, compost, sewage sludge, sedimentary deposition, and tyre abrasion are expected to be found in soil. However, representative and comprehensive information is missing on the sources, transport, and fate. Therefore, a reliable analysis method for microplastics in soils needs to be developed.
The presented work describes the development of a procedure for microplastics analysis in soils. A representative sampling based on the on-site conditions and a sample preparation method was established and comprised of a drying step, the separation of microplastic particles > 1 mm, and a density separation for particles < 1 mm. The detection of the large microplastic particles (> 1 mm) was conducted with Attenuated Total Reflection - Fourier Transform infrared Spectroscopy (ATR-FTIR) , while Thermal Extraction Desorption - Gas Chromatography / Mass Spectrometry (TED-GC/MS) was applied for particles < 1 mm, gaining information on the type of polymer and mass fraction. Based on the established method, 14 environmental soil samples ? with different exposure of microplastics from agriculture, industrial sites, roads, and floods were investigated.
Due to the arbitrary microplastic particle distribution among the samples for large microplastics, it was reasoned that the found particles were unrepresentative. In contrast, microplastic particles < 1 mm were discovered in a high mass in soil samples exposed to plastic mulching or fertilization with sewage sludge or compost (0 – 115 mg/kg). On average, microplastic contents detected in soil samples taken from a construction site and an inner-city lake were higher (13 – 238 mg/kg). As expected, microplastic content in soil sampled in proximity to roads was more pronounced in the upper soil layers. In contrast, very remote sampling sites, expectably uncontaminated, did not lead to the detection of microplastic regarding to thermoanalytical detection method.
In a proof of concept experiment several in vivo and in vitro ecotoxicological tests were applied to evaluate the effect of microplastics (tyre abrasion, polystyrene containing hexabromocyclododecane) in natural soils. In summary, while no effects of the examined probes could be detected on higher levels of biological organization after exposures to earthworm E. andrei, significant changes in several oxidative stress related biomarkers were observed.
The majority of ultrasonic devices used for non-destructive testing in civil engineering require contact with the surface of the concrete (specimen), which significantly increases the time required for the measurement. This makes it impractical for extensive investigation of large-scale structures such as bridge decks, foundations, or tunnels.
In a pioneering approach, fluidic oscillators are used as contact
free ultrasonic sources to overcome the aforementioned limitations. These robust and cost-effective actuators require only pressurised air and are ideally suited for harsh environments. At a constant supply pressure, they generate a continuous monofrequent actuation signal. Further, varying the supply pressure via a fast pressure regulator was found to generate a frequency modulated signal which enabled time-of-flight measurement with an added advantage of increased signal to noise ratio. To demonstrate the feasibility of this novel idea of non-contact ultrasound, the results of the initial tests are presented.
The evaluation of technical components and materials in terms of condition and quality with the aid of non-destructive testing methods plays an outstanding role both in industrial serial production and in the individual assessment of components. The ultrasonic echo method is used for a wide variety of testing tasks, such as measuring the thickness of a component. At the Bundesanstalt für Materialforschung und -prüfung (BAM) in Berlin, test methods are developed and their performance is demonstrated. For this purpose, references such as materials, test procedures or data sets are generated, which are used to evaluate these developed test methods. An important component of these references are data sets that are created according to the BAM Data Policy and made available to the scientific community and users of test methods in practice on the basis of the FAIR principles (Findability, Accessibility, Interoperability, and Reuse).
The use of renewable energy sources, electromobility, and portable
electronics relies on lithium-ion batteries (LIBs). However, one
detrimental effect, which can result in significant performance loss,
is the corrosion of the current collectors caused by the aging
mechanisms, especially in high-energy-density batteries
Glow discharge optical emission spectroscopy (GD-OES) provides
depth profile analysis through sputtering using argon plasma, which
enables the analysis of the corrosion behavior at different depths of
the cathodes.
Compact NMR Spectroscopy in the field: A Versatile Tool for Automated Continuous-Flow Production
(2022)
Chemical companies must find new paths to successfully survive in a changing environment. The potential of digital technologies belongs to these. Flexible and modular chemical plants can produce various high-quality products using multi-purpose equipment with short downtimes between campaigns and reduce time to market for new products. Intensified continuous production plants allow for difficult to produce compounds.
Therefore, fully automated “chemical” process control along with real-time quality control are prerequisites to such concepts and thus should be based on “chemical” information. A commercially available benchtop NMR spectrometer was integrated to the full requirements of an automated chemical production environment such as, e.g., explosion safety, field communication, and robust evaluation of sensor data. It was thereof used for direct loop advanced process control and real-time optimization of the process. Field studies in modular and conventional production plant setups show promising results gaining process knowledge for further optimization. NMR appeared as preeminent online analytical method and allow using a modular data analysis tool, which even served as reliable reference method for further PAT applications (e.g. NIR spectroscopy). In the future, such fully integrated and intelligently interconnecting “smart” systems and processes can speed up the high-quality production of specialty chemicals and pharmaceuticals.
Compact NMR Spectroscopy in the field: A Versatile PAT Tool for Production of Specialty Chemicals
(2022)
Companies of chemical industry find themselves more often in a rapidly changing environment, e.g., due to variability of raw material quality or energy costs and efficiency. Process optimization and new process concepts become more and more important. For example, flexible and modular chemical plants can produce various high-quality products using multi-purpose equipment with short downtimes between campaigns and reduce time to market for new products. Intensified continuous production plants allow for difficult to produce compounds like exothermic reactions with high heat dissipation.
Therefore, fully automated “chemical” process control along with real-time quality control are prerequisites to such concepts and thus should be based on “chemical” information. A commercially available benchtop NMR spectrometer was integrated to the full requirements of an automated chemical production environment such as explosion safety, field communication, and robust evaluation of sensor data. Field studies in modular and conventional production plant setups show promising results gaining process knowledge for further optimization. NMR appeared as preeminent online analytical method and allow using a modular data analysis approach, which can even serve as reliable reference method for further calibration-dependent PAT applications (e.g., NIR spectroscopy). Based on experiences from these field studies an improved analyzer enclosure setup was developed and built, including the option of a secondary method besides NMR spectroscopy. Integrated control systems allow for a flexible implementation based on the available automation infrastructure at the chemical plant or pilot plant setup. In the future, fully integrated and intelligently interconnecting “smart” PAT systems and processes have the potential speed up the setup of production equipment for chemicals and pharmaceuticals and therefore help to reduce the time-to-market.
Compact NMR Spectroscopy in the field: A Versatile PAT Tool for Production of Specialty Chemicals
(2022)
Chemical companies must find new paths to successfully survive in a changing environment, especially by utilizing the potential of digital technologies. Flexible and modular chemical plants can produce various high-quality products using multi-purpose equipment with short downtimes between campaigns and reduce time to market for new products.
Therefore, fully automated process control along with real-time quality control are prerequisites to such concepts and thus should be based on “chemical” information. A commercially available benchtop NMR spectrometer was integrated to the full requirements of chemical production environment such as explosion safety, field communication, and robust evaluation of sensor data. It was used for direct loop advanced process control and real-time optimization of the process. Field studies in modular and conventional production plants show promising results gaining process knowledge. NMR appeared as preeminent online analytical method and allow using a modular data analysis tool, which even served as reliable reference method for further PAT applications (e.g. NIR spectroscopy). In the future, fully integrated and interconnecting “smart” systems and processes can speed up the high-quality production of specialty chemicals and pharmaceuticals.
Compact NMR Spectroscopy in the field: A Versatile PAT Tool for Production of Specialty Chemicals
(2022)
Chemical companies must find new paths to successfully survive in a changing environment, especially by utilizing the potential of digital technologies. Flexible and modular chemical plants can produce various high-quality products using multi-purpose equipment with short downtimes between campaigns and reduce time to market for new products.
Therefore, fully automated process control along with real-time quality control are prerequisites to such concepts and thus should be based on “chemical” information. A commercially available benchtop NMR spectrometer was integrated to the full requirements of chemical production environment such as explosion safety, field communication, and robust evaluation of sensor data. It was used for direct loop advanced process control and real-time optimization of the process. Field studies in modular and conventional production plants show promising results gaining process knowledge. NMR appeared as preeminent online analytical method and allow using a modular data analysis tool, which even served as reliable reference method for further PAT applications (e.g. NIR spectroscopy). In the future, fully integrated and interconnecting “smart” systems and processes can speed up the high-quality production of specialty chemicals and pharmaceuticals.
11 laser printers from 5 manufacturers were purchased in 2017 and tested for their UFP emissions. Size resolved sampling of the emitted particles was done with a 13 stage (30 nm to 10 µm) low pressure cascade impactor. The sampled particles were analysed for their chemical composition by thermal extraction (vaporization at 290°C) followed by GC-MS analysis. High boiling cyclic siloxanes (D10 to D16) were detected as constituents of UFP from laser printers. In comparison to measurements in 2008, aliphatic long-chain alkanes (C22 to C34) were detected additionally as chemical constituents of UFP from most of the tested printers and their amounts were higher than for cyclic siloxanes. Printers of one manufacturer showed very low UPF emissions compared to the other manufacturers.
Bisphenol A (BPA) is used in Polycarbonate, Polyacrylic resins, Polysulfones, Epoxy resins, and Polyetherimides. It is also used in recycled Polyvinyl chloride [1–3]. BPA has been classified as a substance of very high concern (SVHC) under REACH [4] due to its endocrine disrupting properties. The German competent authorities want to reduce the content of BPA in the environment. Possible substitutes for BPA are Bisphenol B (BPB), Bisphenol E (BPE),
Bisphenol F (BPF), or Bisphenol S (BPS), as they are similar in structure.
BPA-based materials have a wide area of application especially outside. These outdoor applications are exposed to different external influences, including physical, biological, mechanical and chemical influences. This results in damage and aging of the material with leaching or migration into the environment. There, the substance is transformed by various transformation processes. The emerging metabolites and transformation products (TPs) can have different properties than the parent substance. Understanding the fate and behavior of the emerging pollutants is very important.
Therefore, different transformation products of selected bisphenols will be generated and analyzed:
To investigate the fate of different bisphenols in water treatment plants technical transformation products [5] will be generated by chlorination, ozonization, the Fenton reaction, and UV-radiation.
For the investigation of the fate of Bisphenols in surface water global radiation will be simulated with UVA-lamps
Simulation of phase-I-metabolism with an electrochemical cell coupled to mass spectrometry (EC-MS).
Thermographic non-destructive testing is based on the interaction of thermal waves with inhomogeneities. The propagation of thermal waves from the heat source to the inhomogeneity and to the detection surface according to the thermal diffusion equation leads to the fact that two closely spaced defects can be incorrectly detected as one defect in the measured thermogram. In order to break this spatial resolution limit (super resolution), the combination of spatially structured heating and numerical methods of compressed sensing can be used. The improvement of the spatial resolution for defect detection then depends in the classical sense directly on the number of measurements. Current practical implementations of this super resolution detection still suffer from long measurement times, since not only the achievable resolution depends on performing multiple measurements, but due to the use of single spot laser sources or laser arrays with low pixel count, also the scanning process itself is quite slow. With the application of most recent high-power digital micromirror device (DMD) based laser projector technology this issue can now be overcome.
Micro-(nano-)encapsulation technology involves building a barrier between the core and the environment and offers several benefits to preserve the functional and physicochemical properties of core material. Tremendous progress has been made in synthesizing well-defined capsules to achieve desired properties such as particle size, chemical composition, and controlled release of loaded compounds.
Encapsulation of volatile organic compounds (VOCs) that could evaporate with a defined rate is of immense interest for application in emission reference materials (ERM). These are urgently needed for quality assurance and quality control purposes (QA/QC) required by test standards for the determination of chemical emissions of construction and other materials for interior use. As such ERMs are hardly available on the market, the EU-funded EMPIR project MetrIAQ was started to fill this gap by developing a material with temporally constant emission of VOCs typically found in indoor air.
Die Thermo Extraktion Desorption Gas Chromatograpie Massen Spektrometrie (TED-GC/MS) ist ein schnelles thermoanalytisches Verfahren zur Bestimmung von Gehalten an Mikroplastik (MP). Die Kombination aus teils schwerflüchtigen Analyten und Kältebrücken führt zu Memory-Effekten, denen u.a. durch häufige Blindwertmessungen begegnet werden muss. Reduzierte Probedurchsätze sind die Folge. Um Messergebnisse abzusichern und den Gerätestatus bei gleichzeitig hoher Messleistung überwachen zu können, wurde die sequentielle Standardmethode überarbeitet.
Im Rahmen von der BAM und anderen Partnern ins Leben gerufene Initiative „Digitale Qualitätsinfrastruktur“ ist der Fokus auf die Entwicklung von neuen Regelwerken und Zertifizierungsworkflows ausgerichtet. Dabei ist eine besondere Bedeutung dem Zusammenführen von Operational Technology (OT) und Informationstechnik (IT) beizumessen, wenn aktuelle Prozess- und Parameterdaten
zuverlässig zur Verfügung gestellt werden sollen. In dem Use Case Wasserstofftankstelle werden digitale Abbilder erprobt, die u.a. der Kalibrierung von Sensoren, dem Nachweis über die Wasserstoffreinheit und der vorausschauenden Wartung dienen sollen.
Großenteils der verfahrenstechnischen Bestandsanlagen, die sogenannten Brownfield-Anlagen, sind nach einem konservativen und hierarchischen Automatisierungskonzept ausgelegt. Hierbei können sämtliche Prozessdaten,
besonders aus der Feldebene, einer oberen informationstechnische Ebene
unzugänglich bleiben. Eine Brückentechnologie nach der NAMUR Open Architecture (NOA) soll möglichst viele Informationen und Daten aus der vorgegebenen Brownfield-Automatisierung sicher und rückwirkungsfrei zur
Verfügung stellen. Zusätzliche Sensorik soll ebenso zu der Datenerweiterung beitragen und letztendlich den digitalen Zwilling, bzw. das digitale Abbild des verfahrenstechnischen Prozesses, ergänzen.
Die Herausforderungen einer solchen Infrastruktur gelten vor allem einer universellen
Kommunikationsschnittstelle und der Sicherheit. Darüber hinaus werden vorgeschlagene Normen und Empfehlungen untersucht und erprobt.
Per- and polyfluoroalkyl substances (PFAS) are a large group of organofluorine surfactants used in the formulations of thousands of consumer goods, including aqueous film-forming foams (AFFF) used to suppress aviation fires in training scenarios, non-stick cookware, fast-food wrappers, water-repellent fabrics, medical equipment, and plastic and leather products. As a result of the perpetual use of PFAS containing products, effluents and sewage sludge from wastewater treatment plants (WWTPs) have been observed to be an important pathway for PFAS into the environment. In Germany, phosphorus and other nutrients from sewage sludge and wastewater should be recycled in WWTPs of cities with a large population. However, it is not clear if PFAS contamination from wastewater and sewage sludge end up in novel wastewater-based fertilizers. Normally, PFAS are analyzed using PFAS protocols typically with time-consuming extraction steps and LC-MS-MS quantification. However, for screening of PFAS contaminations in sewage sludge or wastewater-based fertilizers also passive sampler based on the Diffusive Gradients in Thin-films (DGT) technique can be used for the PFAS extraction. Afterwards, combustion ion chromatography (CIC) can be applied to analyse the “total” amount of PFAS on the passive sampler. Here, we show results from the DGT method in comparison to those of the extractable organic fluorine (EOF) method for a variety of wastewater-based fertilizers. Additionally, we analysed the adsorption of PFAS on the weak anion exchanger (WAX) based DGT passive sampler binding layer by infrared and fluorine K-edge X-ray adsorption near-edge structure (XANES) spectroscopy.
Safe food is a prerequisite for good human health, however currently almost one in ten people in the world fall ill after eating contaminated food. National food safety authorities need to be able to manage food safety risks along the entire food chain. The Official Controls Regulation (EU) 2017/625 was put in place to ensure that food and feed law stipulates the need for validated analytical methods. However, whilst method development for food control and proficiency testing are well established by European Union Reference Laboratories and National Reference Laboratories, validation of the measurements involved, certified reference materials and internationally recognised calibration and measurement capabilities are currently often (?) lacking. This may erode trust in the accuracy of the measurements.
This poster presents Food-MetNet, a coordinated preparatory initiative to establish the European Metrology Network for Safe and Sustainable Food, recently approved by the European Association of National Metrology Institutes (EURAMET). Food-MetNet aims to establish an ongoing dialogue between the metrology community, reference laboratories and regulatory bodies, in order to (i) identify stakeholders’ needs, (ii) develop a sustainable knowledge-sharing programme and web-based platform for stakeholders and (iii) develop roadmaps and a strategic research agenda. Improved access to more reliable and accurate food safety measurements will enable reference laboratories to more confidently and effectively compare their measurement results and support accreditation. This is particularly important where national food safety authorities need to assess potential new contaminants, novel food ingredients and newly emerging food risks, and new measurements methods may be required as well as input into new documentary standards. The activities for sustainable food intend to boost the activity within the "EU green deal framework" to reduce food waste and losses, and the development of standards and methods that allow for the reuse of food waste. The support to new business opportunities and innovation will allow increasing the market competitiveness of EU food industries and the valorisation of waste by reducing environmental impacts.
Contamination of the environment with antibiotics is of great concern as it promotes the evolution of antimicrobial resistances. In case of amoxicillin (AMX) in the aquatic environment, further risk arises from hydrolysis products (HPs) which can cause allergy. To assess these risks, a comprehensive investigation and understanding of the degradation of AMX is necessary. We investigated the hydrolysis rate of AMX in different types of water as well as the influence of temperature and irradiation. The content of the heavy metal ions copper and zinc was found to be crucial for the hydrolysis rate of AMX and stability of HPs. Eventually, a new degradation pathway for AMX could be elaborated and confirmed by tandem mass spectrometry (LC-MS/MS).
Contamination of drinking water with pharmaceuticals is an emerging problem and a potential health threat. Immunochemical methods based on the binding of the analyte to specific antibodies enable fast & cost-effective on-site analyses. Magnetic bead-based immunoassays (MBBAs) allow for implementation into an immunosensor for online testing. Particles are prepared by either coupling the analyte molecule (diclofenac) or the respective antibody (amoxicillin) to the surface. For miniaturization, detection is performed electrochemically (chronoamperometry) on a microfluidic chip. The developed immunosensor will enable detection of pharmaceuticals directly in water supply pipes.
Contamination of drinking water with pharmaceuticals is an emerging problem and a potential health threat. Immunochemical methods based on the binding of the analyte to specific antibodies enable fast & cost-effective on-site analyses. Magnetic bead-based immunoassays (MBBAs) allow for implementation into an immunosensor for online testing. Particles are prepared by either coupling the analyte molecule (diclofenac) or the respective antibody (amoxicillin) to the surface. For miniaturization, detection is performed electrochemically (chronoamperometry) on a microfluidic chip. The developed immunosensor will enable detection of pharmaceuticals directly in water supply pipes.
Fumonisins are a class of toxic secondary metabolites produced by various Fusarium species. The two most important producers of fumonisins are F. verticillioides and F. proliferatum but also Aspergillus niger is known to produce fumonisins. Most frequently they occur on maize, but also other grains can be contaminated with this group of mycotoxins. Exposure to fumonisins by dietary intake can have serious health effects on farm animals such as equine leukoencephalomalacia and porcine pulmonary oedema and is associated with neural tube defects and esophageal cancer in humans. Thus, the European Commission sets legal limits for fumonisins in foodstuffs. The detection of fumonisins is frequently performed in laboratories by chromatographic methods, which are costly and require trained personnel. Simplifying the analysis is therefore a major goal using portable detection systems. Electrochemical enzymatic biosensors offer great promise to meet this demand. Here we report for the first time an enzymatic fumonisin sensing approach with amperometric detection. For this purpose, an Aspergillus niger fumonisin amine oxidase (AnFAO) catalyzing the oxidative deamination of fumonisins, producing hydrogen peroxide, was recombinantly produced in E. coli. For the first time, the specific enzyme activity of AnFAO was determined using a horseradish peroxidase-based fluorescence assay. It was found that the specific activity of AnFAO using 20 μM Fumonisin B1 as substrate is higher than for 20 μM Fumonisin B2 with 0.122 U mg-1 and 0.058 U mg-1, respectively. It was possible to show a dependence of enzyme activity with enzyme – and substrate-concentration. For fumonisin B1 detection, the enzyme was coupled covalently to magnetic particles and the enzymatically produced H2O2 was detected amperometrically in a flow injection system using Prussian blue carbon electrodes. The developed method allows to quantify fumonisin B1 concentrations down to 1.5 µM and demonstrates that the recombinantly produced AnFAO was able to deaminate different concentrations of fumonisin even in immobilized form. Thus, this enzyme is well suited to develop an enzyme based electrochemical biosensor for fumonisin contaminated food and feed.
High demand for remote sensing of hazardous substances. Possible solution: Use of distributed, low cost, and environmentally safe particles as passive sensors that can be read out remotely
Chemical intelligence on the particle surface can be easily modified Particles enable optically quantifiable response and inference of target substances (also no maintenance or power supply required
Screening against ADAMTS4 reveals a specific peptide, which was turned into an MRI probe. The aneurysm in a mouse modal was visualized via MRI. A differentiation between stable and unstable aneurysm in an early state was performed. Using the probe as tool for an easy and non-invasive rupture assessment is possible.
Nanoparticles (NPs) have become important materials for a variety of chemical technologies, including catalysis. One of the main challenges is the reduction of green house gases, such as CO2. One opportunity besides the capturing is the conversion to synthesis gas via the reverse water-gas shift reaction.
A facile and efficient method is described for the solvothermal synthesis of size-tunable, stable, and uniform NiCu core-shell NPs. The diameter of the NPs can be tuned in a range from 6 nm to 30 nm and the Ni:Cu ratio from 30:1 to 1:1. The NPs are structurally characterized with combination of transmission electron microscopy, anomalous small-angle X-ray scattering, X-ray photoelectron spectroscopy, and X-ray absorption fine structure. Using these analytical methods, a core-shell-shell structure their chemical composition is elucidated. A depletion from the core to the shell is observed, with the core consisting of NiCu alloy, surrounded by an inner Ni-rich shell and an outer NiO shell. The SiO2-supported NiCu core-shell NPs show pronounced selectivity of >99% for CO in the catalytic reduction of CO2 to CO using hydrogen as reactant (reverse water–gas shift reaction).
Steps Forward in the Application of 3,3’,5,5’- Tetramethylbenzidine (TMB) in Amperometric Assays
(2022)
Electrochemical methods make great promise to meet the demand for user-friendly on-site devices for monitoring important parameters. Food industry often runs own lab procedures, e.g. for mycotoxin analysis, but it is a major goal to simplify analysis, linking analytical methods with miniaturized technologies. Enzyme-linked immunosorbent assays, with photometric detection of the horseradish peroxidase (HRP) substrate, 3,3’,5,5’-tetramethylbenzidine (TMB), form a good basis for sensitive detection. To provide a straight-forward approach for the miniaturization of the detection step, we have studied the pitfalls of the electrochemical TMB detection. By cyclic voltammetry it was found that the TMB electrochemistry is strongly dependent on the pH and the electrode material.
It was found that screen-printed gold electrodes and a highly acidic pH value (pH 1) are well-suited to perform the electrochemical detection of TMB, due to the reversible character of the redox reaction under these conditions. This set-up provides a good signal stability over several measuring cycles, providing the basis for analysing multiple samples. In contrast to this, for carbon screen-printed electrodes, it was found that the signal response has changed after the electrochemical reaction with TMB at pH 1. At a weakly acidic pH value (pH 4), neither with carbon nor with gold electrodes a reproducible electrochemical detection of TMB could be achieved [1].
Based on these findings we created a smartphone-based, electrochemical, immunomagnetic assay for the detection of ochratoxin A and ergometrine in real samples. Therefore, a competitive assay was performed on magnetic beads using HRP and TMB/H2O2 to generate the signal. Enzymatically oxidized TMB was quantified after addition of H2SO4 by amperometry with screen-printed gold electrodes in a custom-made wall-jet flow cell. The results are in good correlation with the established photometric detection method, providing a solid basis for sensing of further analytes in HRP-based assays using the newly developed miniaturized smartphone-based, electrochemical, immunomagnetic assay.
Morpho-Chemical Characterisation of Me-TiO2 Nanoparticles for Enhanced Photocatalytical Activity
(2022)
The conversion of solar energy into electricity and solar fuels is of crucial importance for a green and sustainable future. Water splitting using semiconductor photo-catalysts is considered a sustainable method to produce clean hydrogen (H2) fuel. Nevertheless, H2 photo-production efficiency remains still low, although extensive research works to understand better the mechanisms of the Hydrogen Evolution Reaction (HER) and the Oxygen Evolution Reaction (OER) are being carried out. In this respect, TiO2 is a key photoactive material, usually employed with a co-catalyst deposited onto the surface to enhance charge carriers’ separation and catalyze surface charge transfer reactions. The deposition of a co-catalyst on the TiO2 nanoparticle surface represents one successful way to enhance the activity of the photocatalyst through a modification of its surface and redox properties. In this context, high-resolution scanning electron microscopy coupled with elemental analysis by energy-dispersive X-ray spectroscopy (EDS) is fundamental for studying and understanding the effect of the nanoparticle morphology on the functional properties of shape-controlled TiO2 crystals (bipyramides, platelets, and elongated particles). Different types of metal-semiconductor combinations, TiO2 shapes and dopant metals (Ag, Pt, etc) and metal concentrations will be discussed.
The recent development of x-ray photoelectron spectroscopy using excitation sources different from the usual lab-source Mg Kα and Al Kα and spectrometers with more sophisticated lens systems requires flexible approaches for determining the transmission function. Therefore, the approach using quantified peak areas (QPA) was refined.1 A new algorithm allows a more precise estimation of the transmission function which could be shown by comparing the results obtained with the new version with former calculations. Furthermore, next to the established reference materials Cu, Ag and Au, ionic liquids can be used for estimating the transmission function at beamlines with variable excitation energies. Comparison between the measured and stoichiometric composition shows that a transmission function was determined which allows a reasonable quantification.
The isotopic analysis of lithium is also relevant to the study of geological phenomena.1 In this work we propose improvements to the method for the isotopic analysis of lithium using a high-resolution continuum source atomic absorption spectrometer (HR-CS-AAS) coupled to a double echelle modular spectrometer (DEMON). 2 This tool for isotopic ratio determination is based on monitoring the isotopic components of lithium by their spin-orbit coupling and its isotopic shift of about 15 pm for the 22P←2 2S electronic transition around 670.788 nm. The data analysis was carried out by using a decision-tree-based ensemble machine learning (ML) algorithm. For the training of the algorithm (XGBoost), a set of samples with 6Li isotope amount fractions ranging from 0.06 to 0.99 mol-1 was used. Subsequently, the procedure was validated of a set of stock chemicals (Li2CO3, LiNO3, LiCl and LiOH) and a BAM candidate reference material, the cathode material LiNi1/3Mn1/3Co1/3O2 (NMC111). Finally, the ML model was applied to the set of geological samples, previously digested, for the determination of their isotope ratio. The optical resolution was improved from 140,000 to 790,000 to better deconvolution the lithium isotopic components in the atomic spectrum. And the method was compared with multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The results are metrologically comparable.
Direct laser writing grows to an industry-ready manufacturing platform. A stable quality infrastructure is needed for robust processing. However, flaws, errors or impurities are neither described nor communicated in the community of two-photon polymerization.
In contrast, additive manufacturing errors in metals manufacturing are described thoroughly.
microscopy (AFM), or X-ray reflectometry. For the additional determination of thin film composition, techniques like X-ray photoelectron spectroscopy (XPS) or mass spectrometry-based techniques can be used. An alternative non-destructive technique is electron probe microanalysis (EPMA). This method assumes a sample of homogenous (bulk) chemical composition, so that it cannot be usually applied to thin film samples. However, in combination with the thin film software StrataGEM, the thickness as well as the composition of such films on a substrate can be determined.
This has been demonstrated for FeNi on Si and SiGe on Al2O3 film systems. For both systems five samples with different elemental composition and a reference were produced and characterised by Korean research institute KRISS using inductively coupled plasma mass spectrometry (ICP-MS), Rutherford backscattering (RBS), and transmission electron microscopy (TEM). These samples were used for an international round robin test.
In 2021, a new and open-source thin film evaluation programme called BadgerFilm has been released. It can also be used to determine thin film composition and thickness from intensity ratios of the unknown sample and standards (k-ratios).
In this contribution, we re-evaluated the data acquired for the FeNi and SiGe systems using the BadgerFilm software package and compared the resulting composition and thickness with the results of the established StrataGEM software and other reference methods. With the current evaluation, the BadgerFilm software shows good agreement with the composition and thickness calculated by StrataGEM and as the reference values provided by the KRISS.
MXenes are a new family of two-dimensional (2D) transition metal carbides, carbonitrides, and nitrides discovered in 2011. Among many reported family members, titanium carbide is the most widely studied and explored due to the optimized synthesis conditions and promising characteristics like good mechanical strength, solution processability, and excellent conductivity. Here, we report the development of an electrochemical biosensor involving the amine-functionalized Few-Layered-Titanium Carbide Nanosheets and monoclonal antibodies against the SARS-CoV-2 nucleocapsid protein (anti-SARS-CoV-2 mAb) to design a point-of-care device for detection of the SARS-CoV-2 nucleocapsid protein (SARS-CoV-2 NP) antigen.