Chemische Charakterisierung und Spurenanalytik
Filtern
Dokumenttyp
- Zeitschriftenartikel (71) (entfernen)
Schlagworte
- Mass-Spectrometry (8)
- Mycotoxins (8)
- Cancer (7)
- Food (5)
- Transformation products (5)
- Electrochemistry (4)
- HRMS (4)
- Mass Spectrometry (4)
- Mass spectrometry (4)
- Metabolomics (4)
- Metrology (4)
- Tumor metabolism (4)
- Fatty acid metabolism (3)
- Food analysis (3)
- Lipidomic profile (3)
- Mass Spectroscopy (3)
- Metabolic stress (3)
- Mycotoxin (3)
- Quality assurance (3)
- Adsorption (2)
- Analytical Chemistry (2)
- Certified reference material (2)
- Ergot alkaloids (2)
- Fluorescence (2)
- Gas chromatography (2)
- HPLC-MS/MS (2)
- Hydrazinolysis (2)
- Interlaboratory comparison (2)
- MYCN (2)
- Purity assessment (2)
- R package (2)
- Reference material (2)
- Reproducibility (2)
- Transformation product (2)
- Volatile organic compounds (2)
- 2,5-dihydroxyacetophenone (1)
- ABID (1)
- Acrylamide (1)
- Aflatoxins (1)
- Altenuene (1)
- Alternaria mycotoxins (1)
- Aluminum (1)
- Analyseverfahren (1)
- Analytical methods (1)
- Antagonists (1)
- Antibody identification (1)
- App (1)
- Aspergillus (1)
- BERM (1)
- Benz[a]anthracene (BaA) (1)
- Benzo[a]pyrene (BaP) (1)
- Bioconjugation (1)
- Biosynthesis (1)
- Biotests (1)
- Biotransformation (1)
- Bisphenol-A (1)
- Breath (1)
- CCQM (1)
- CCQM key comparison (1)
- CE/MC-ICP-MS (1)
- COVID-19 (1)
- Cadmium (1)
- Cancer awareness measure (1)
- Cancer cells (1)
- Cancer risk (1)
- Cancer therapy (1)
- Canine olfactometry (1)
- Chemical Safety (1)
- Cleavage (1)
- Cocoa (1)
- Combustion Ion Chromatography (1)
- Complexation (1)
- Conjugate (1)
- Consumer Products (1)
- Corona virus (1)
- DHAP (1)
- Data processing (1)
- Debromination (1)
- Derivatization (1)
- Dimerization (1)
- Dried fig (1)
- EC/LC/MS (1)
- EC/MS (1)
- ECR (1)
- Electrochemical Reactor (1)
- Electrochemical oxidation (1)
- Electrochemistry mass spectrometry (1)
- Emerging brominated flame retardant (1)
- Emerging contaminants (1)
- Emerging/novel brominated flame retardant (1)
- Esterification (1)
- Ethyl glucuronide (1)
- European Reference Material (1)
- Extraction (1)
- Fatty acid desaturation (1)
- Fatty acid synthesis (1)
- Fatty acid uptake (1)
- Fatty acids (1)
- Fenton’s reagent (1)
- Fertilizer (1)
- Fluorophilic interactions (1)
- Fluxomics (1)
- Folic acid (1)
- Food Analysis (1)
- Food contaminants (1)
- Food fermentation (1)
- Food safety (1)
- Fungicide (1)
- Fusarium (1)
- Fusarium mycotoxin (1)
- Gas analysis (1)
- Gas chromatography (GC) (1)
- Github (1)
- HLA (1)
- HPLC-DAD/FLD (1)
- Hydrazin (1)
- Hydrolysis (1)
- Hydroxylation (1)
- ICP-ToF-MS (1)
- ISO REMCO (1)
- Identity (1)
- Indoor air (1)
- Interlaboratory key comparison (1)
- Ionophore (1)
- Ionophore antibiotics (1)
- Isotope (1)
- Isotope Labelling (1)
- Isotope dilution (ID) (1)
- Isotope ratio (1)
- Isotope-labeled (1)
- Isotopologue Distribution (1)
- Job plot (1)
- LC-MS/MS (1)
- LC/HRMS (1)
- Lasalocid (1)
- Laser Ablation/Imaging (1)
- Library (1)
- Light chain (1)
- Lipid metabolism (1)
- Lipidomics (1)
- Liquid chromatography (1)
- Liquid chromatography (LC) (1)
- Lung cancer (1)
- Lysergic acid hydrazide (1)
- MALDI (1)
- MC-ICP-MS (1)
- MOSH/MOAH (1)
- Mass spectrometry (MS) (1)
- Mass-spectrometry (1)
- Massenspektrometrie (1)
- Metabolic Flux (1)
- Metabolism (1)
- Metabolization (1)
- Method development (1)
- Microbe interactions (1)
- Mineral oil hydrocarobons (1)
- Mobile analysis (1)
- Mobile analytics (1)
- Modified mycotoxins (1)
- Monensin (1)
- Monoclonal antibody (1)
- Moxidectin (1)
- Mycotoxin Analysis (1)
- NIST-mAb 8671 (1)
- NMR (1)
- Nanomaterials (1)
- Network (1)
- Non-target (1)
- Non-targeted analysis (1)
- Nucleocapsid (1)
- On-site detection (1)
- Open science (1)
- Organic Synthesis (1)
- Organic contaminants (1)
- Oxidative metabolism (1)
- PAH (1)
- PAHs (1)
- PFAS (1)
- Peptide mass fingerprinting (1)
- Peptides (1)
- Per- and Polyfluoroalkyl substances (PFAS) (1)
- Pesticide (1)
- Photochemistry (1)
- Photodegradation (1)
- Polycyclic aromatic hydrocarbon (PAH) (1)
- Polycyclic aromatic hydrocarbons (1)
- Polyurethanes (1)
- Priority effect (1)
- Proficiency testing (1)
- Pulverization (1)
- Pyrolysis (1)
- Quality Assurance (1)
- Quality control (1)
- Quantitative determination (1)
- RBD (1)
- Rat/human liver microsomes (1)
- Recombinant antibody (1)
- Reference Material (1)
- Reference materials (1)
- Remediation (1)
- Renal disease (1)
- Reversible covalent hydrazine chemistry (RCHC) (1)
- Rhizopus (1)
- Rhizopus and Aspergillus oryzae (1)
- SDHI-fungicide (1)
- SIDA-LC-MS/MS (1)
- SOM-SM (1)
- Safety (1)
- Salinomycin (1)
- Screening method (1)
- Sensors (1)
- Sequence coverage (1)
- Sequencing (1)
- Sewage sludge (1)
- Society of hair testing (1)
- Software (1)
- Speiseöle (1)
- Spike protein (1)
- Stakeholders (1)
- Standardization (1)
- Standards (1)
- Sum Parameter (1)
- Sum Parameter Method (1)
- Sum parameter method (1)
- Sustainable Food Safety (1)
- Suzuki coupling (1)
- TGA-FTIR (1)
- Thermal decomposition (1)
- Thermal degradation (1)
- Thermo-desorption (1)
- Toxicity testing (1)
- Toys (1)
- Traceability (1)
- Transformationsprodukte (1)
- Transient signal (1)
- Truffle (1)
- Truffle Aroma (1)
- Tryptic digest (1)
- Tuber melanosporum (1)
- UV irradiation (1)
- Urine (1)
- VOC (1)
- Validation trial (1)
- Vegetable edible oil (1)
- Veterinary drugs (1)
- Volatile marker (1)
- Volatile organic compounds; (1)
- Yerba mate tea (1)
- Zearalenone (1)
- Zearalenone sulfate (1)
- Zenodo (1)
- a-zearalenol (1)
- species-specific isotope information (1)
Organisationseinheit der BAM
- 1.7 Organische Spuren- und Lebensmittelanalytik (71) (entfernen)
Volatile organic compounds (VOCs) are of interest in many different fields. Among them are food and fragrance analysis, environmental and atmospheric research, industrial applications, security or medical and life science. In the past, the characterization of these compounds was mostly performed via sample collection and off-site analysis with gas chromatography coupled to mass spectrometry (GC-MS) as the gold standard. While powerful, this method also has several drawbacks such as being slow, expensive, and demanding on the user. For decades, intense research has been dedicated to find methods for fast VOC analysis on-site with time and spatial resolution. We present the working principles of the most important, utilized, and researched technologies for this purpose and highlight important publications from the last five years. In this overview, non-selective gas sensors, electronic noses, spectroscopic methods, miniaturized gas chromatography, ion mobility spectrometry and direct injection mass spectrometry are covered. The advantages and limitations of the different methods are compared. Finally, we give our outlook into the future progression of this field of research.
Despite numerous advantages offered by hyphenation of chromatography and electrokinetic separation methods with multicollector (MC) ICP-MS for isotope analysis, the main limitation of such systems is the decrease in precision and increase in uncertainty due to generation of short transient signals. To minimize this limitation, most authors compare several isotope ratio calculation methods and establish a multi-step data processing routine based on the precision and accuracy of the methods. However, to the best of our knowledge, there is no universal data processing tool available that incorporates all important steps of the treatment of the transient signals. Thus, we introduce a data processing application (App) IsoCor that facilitates automatic calculation of isotope ratios from transient signals and eases selection of the most suitable method. The IsoCor App performs baseline subtraction, peak detection, mass bias correction, isotope ratio calculation and delta calculation. The feasibility and reliability of the App was proven by reproducing the results from isotope analysis of three elements (neodymium, mercury and sulfur) measured on-line via hyphenated systems. The IsoCor App provides trackability of the results to ensure quality control of the analysis.
The aim of this study was to identify specific truffle marker substances within the truffle aroma. The aroma profile of different truffle species was analyzed using static headspace sampling with gas chromatography mass spectrometry analysis (SHS/GC-MS). Possible marker substances were identified, taking the additional literature into account. The selected marker substances were tested in an experiment with 19 truffle dogs. The hypothesis “If trained truffle dogs recognize the substances as supposed truffles in the context of an experiment, they can be regarded as specific” was made. As it would be nearly impossible to investigate every other possible emitter of the same compounds to determine their specificity, this hypothesis was a reasonable approximation. We were interested in the question of what it is the dogs actually search for on a chemical level and whether we can link their ability to find truffles to one or more specific marker substances. The results of the dog experiment are not as unambiguous as could have been expected based on the SHS/GC-MS measurements. Presumably, the truffle aroma is mainly characterized and perceived by dogs by dimethyl sulfide and dimethyl disulfide. However, as dogs are living beings and not analytical instruments, it seems unavoidable that one must live with some degree of uncertainty regarding these results.
Rapid, cost-efficient, and eco-friendly methods are desired today for routine analysis of the Fusarium mycotoxin zearalenone (ZEN) in edible vegetable oils. Liquid chromatography with fluorescence detection (HPLC-FLD) is commonly used to reliably control the specified ZEN maximum levels, which requires efficient sample clean-up to avoid matrix interferences. Therefore, a highly selective extraction and clean-up method based on reversible covalent hydrazine chemistry (RCHC) using hydrazine-functionalized silica was developed. This efficient solid-phase extraction (SPE) involves reversible hydrazone formation of ZEN with the hydrazine moiety covalently bound to a solid phase. Optimal conditions were achieved with 1 mL SPE cartridges filled with 400 mg of hydrazine-functionalized silica. The developed RCHC-SPE method was validated in an interlaboratory comparison study (ILC) with twelve participants analyzing six edible vegetable oils with a focus on maize oils. The derived method parameters (ZEN recovery 83%, repeatability 7.0%, and reproducibility 18%) meet the performance criteria of Commission Regulation (EC) No 401/2006. The developed RCHC-SPE-based HPLC-FLD method allows the reliable quantification of ZEN in the range of 47–494 μg/kg for different types of edible vegetable oils, also for matrix-reach native oils. Due to the high efficiency, the significantly reduced matrix load helps to extend the lifetime of analytical equipment. Furthermore, the re-useability of the RCHC-SPE cartridges contributes to an eco-friendly approach and reduced analysis costs. To our knowledge, this is the first report on ZEN quantification in edible vegetable oils based on manual RCHC-SPE cartridges. Due to its high performance, the developed RCHC-SPE method is a promising alternative to the current European standard method EN 16924:2017 (HPLC-FLD part).
Analysis of electrochemical and liver microsomal transformation products of lasalocid by LC/HRMS
(2022)
Rationale: Lasalocid (LAS), an ionophore, is used in cattle and poultry farming as feed additive for its antibiotic and growth-promoting properties. Literature on transformation products (TP) resulting from LAS degradation is limited. So far, only hydroxylation is found to occur as the metabolic reaction during the LAS degradation. To investigate potential TPs of LAS, we used electrochemistry (EC) and liver microsome (LM) assays to synthesize TPs, which were identified using liquid chromatography high-resolution mass spectrometry (LC/HRMS).
Methods: Electrochemically produced TPs were analyzed online by direct coupling of the electrochemical cell to the electrospray ionization (ESI) source of a Sciex Triple-TOF high resolution mass spectrometer. Then, EC-treated LAS solution was collected and analyzed offline using LC/HRMS to confirm stable TPs and improve their annotation with a chemical structure due to informative MS/MS spectra. In a complementary approach, TPs formed by rat and human microsomal incubation were investigated using LC/HRMS. The resulting data were used to investigate LAS modification reactions and elucidate the chemical structure of obtained TPs.
Results: The online measurements identified a broad variety of TPs, resulting from modification reactions like (de-)hydrogenation, hydration, methylation, oxidation as well as adduct formation with methanol. We consistently observed different ion complexations of LAS and LAS-TPs (Na+; 2Na+ K+; NaNH4 +; KNH4 +). Two stable methylated EC-TPs were found, structurally annotated, and assigned to a likely modification reaction. Using LM incubation, seven TPs were formed, mostly by oxidation/hydroxylation. After the identification of LM-TPs as Na+-complexes, we identified LM-TPs as K+-complexes.
Conclusion: We identified and characterized TPs of LAS using EC- and LM-based methods. Moreover, we found different ion complexes of LAS-based TPs. This knowledge, especially the different ion complexes, may help elucidate the metabolic and environmental degradation pathways of LAS.
Lifestyle modifications could prevent almost one‑third to one‑half of all cancer cases. The awareness of cancer risk factors could motivate people to make such changes in their behaviors and lifestyles. This work aims to investigate the cancer awareness level in the Pakistani population. Telephone interviews of 657 individuals in Pakistan were carried out using the Cancer Awareness Measure (CAM) and Cancer Awareness Measure–MYthical Causes Scale (CAM‑MY). We observed that participants scored significantly better on the CAM scale than the CAM‑MY scale, and CAM scores were negatively associated with CAM‑MY scores. Years of formal education or a biology major at undergraduate or graduate level did not affect our population’s cancer awareness levels. Age displayed a weak but statistically significant negative association with CAM scores. Most participants failed to identify modifiable cancer risk factors, e.g., low physical activity. Efforts should be made to improve awareness of modifiable risk factors. We observed that brief training sessions could markedly improve people’s understanding of cancer risk factors and myths.
For more than 110 years, BAM has been producing reference materials for a wide range of application fields. With the development of new analytical methods and new applications as well as continuously emerging more stringent requirements of laboratory accreditation with regard to quality control and metrological traceability, the demand and requirements for reference materials are increasing. This trend article gives an overview of general developments in the field of reference materials as well as developments in selected fields of application in which BAM is active. This includes inorganic and metal analysis, gas analysis, food and consumer products, and geological samples. In addition to these more traditional fields of application, developments in the areas of optical spectroscopy, particulary fluorescence methods, and nanomaterials are considered.
Towards Unbiased Evaluation of Ionization Performance in LC-HRMS Metabolomics Method Development
(2022)
As metabolomics increasingly finds its way from basic science into applied and regulatory environments, analytical demands on nontargeted mass spectrometric detection methods continue to rise. In addition to improved chemical comprehensiveness, current developments aim at enhanced robustness and repeatability to allow long-term, inter-study, and meta-analyses. Comprehensive metabolomics relies on electrospray ionization (ESI) as the most versatile ionization technique, and recent liquid chromatography-high resolution mass spectrometry (LC-HRMS) instrumentation continues to overcome technical limitations that have hindered the adoption of ESI for applications in the past. Still, developing and standardizing nontargeted ESI methods and instrumental setups remains costly in terms of time and required chemicals, as large panels of metabolite standards are needed to reflect biochemical diversity. In this paper, we investigated in how far a nontargeted pilot experiment, consisting only of a few measurements of a test sample dilution series and comprehensive statistical analysis, can replace conventional targeted evaluation procedures. To examine this potential, two instrumental ESI ion source setups were compared, reflecting a common scenario in practical method development. Two types of feature evaluations were performed, (a) summary statistics solely involving feature intensity values, and (b) analyses additionally including chemical interpretation.
Results were compared in detail to a targeted evaluation of a large metabolite standard panel. We reflect on the advantages and shortcomings of both strategies in the context of current harmonization initiatives in the metabolomics field.
MALDI-TOF-MS-Based Identification of Monoclonal Murine Anti-SARS-CoV-2 Antibodies within One Hour
(2022)
During the SARS-CoV-2 pandemic, many virus-binding monoclonal antibodies have been developed for clinical and diagnostic purposes. This underlines the importance of antibodies as universal bioanalytical reagents. However, little attention is given to the reproducibility crisis that scientific studies are still facing to date. In a recent study, not even half of all research antibodies mentioned in publications could be identified at all. This should spark more efforts in the search for practical solutions for the traceability of antibodies. For this purpose, we used 35 monoclonal antibodies against SARS-CoV-2 to demonstrate how sequence-independent antibody identification can be achieved by simple means applied to the protein. First, we examined the intact and light chain masses of the antibodies relative to the reference material NIST-mAb 8671. Already half of the antibodies could be identified based solely on these two parameters. In addition, we developed two complementary peptide mass fingerprinting methods with MALDI-TOF-MS that can be performed in 60 min and had a combined sequence coverage of over 80%. One method is based on the partial acidic hydrolysis of the protein by 5 mM of sulfuric acid at 99 degrees C. Furthermore, we established a fast way for a tryptic digest without an alkylation step. We were able to show that the distinction of clones is possible simply by a brief visual comparison of the mass spectra. In this work, two clones originating from the same immunization gave the same fingerprints. Later, a hybridoma sequencing confirmed the sequence identity of these sister clones. In order to automate the spectral comparison for larger libraries of antibodies, we developed the online software ABID 2.0. This open-source software determines the number of matching peptides in the fingerprint spectra. We propose that publications and other documents critically relying on monoclonal antibodies with unknown amino acid sequences should include at least one antibody fingerprint. By fingerprinting an antibody in question, its identity can be confirmed by comparison with a library spectrum at any time and context.
The investigation of metabolic fluxes and metabolite distributions within cells by means of tracer molecules is a valuable tool to unravel the complexity of biological systems. Technological advances in mass spectrometry (MS) technology such as atmospheric pressure chemical ionization (APCI) coupled with high resolution (HR), not only allows for highly sensitive analyses but also broadens the usefulness of tracer‐based experiments, as interesting signals can be annotated de novo when not yet present in a compound library. However, several effects in the APCI ion source, i.e., fragmentation and rearrangement, lead to superimposed mass isotopologue distributions (MID) within the mass spectra, which need to be corrected during data evaluation as they will impair enrichment calculation otherwise. Here, we present and evaluate a novel software tool to automatically perform such corrections. We discuss the different effects, explain the implemented
algorithm, and show its application on several experimental datasets. This adjustable tool is available as an R package from CRAN.