Analytische Chemie
Filtern
Erscheinungsjahr
Dokumenttyp
- Vortrag (2194)
- Zeitschriftenartikel (1943)
- Posterpräsentation (1009)
- Beitrag zu einem Tagungsband (514)
- Sonstiges (128)
- Forschungsbericht (65)
- Forschungsdatensatz (57)
- Buchkapitel (52)
- Dissertation (39)
- Newsletter (38)
- Beitrag zu einem Sammelband (30)
- Tagungsband (Herausgeberschaft für den kompletten Band) (18)
- Zeitschriftenheft (Herausgeberschaft für das komplette Heft) (9)
- Corrigendum (8)
- Handbuch (7)
- Video (5)
- Sammelband (Herausgeberschaft für den kompletten Band) (4)
- Monografie (3)
Sprache
- Englisch (5002)
- Deutsch (1052)
- Mehrsprachig (54)
- Spanisch (5)
- Russisch (4)
- Französisch (3)
- Polnisch (2)
- Italienisch (1)
Schlagworte
- Fluorescence (236)
- Nanoparticles (194)
- LIBS (143)
- Concrete (136)
- XPS (121)
- Quantum yield (117)
- Nanoparticle (112)
- Mechanochemistry (101)
- Zerstörungsfreie Prüfung (101)
- Ultrasound (98)
Organisationseinheit der BAM
- 1 Analytische Chemie; Referenzmaterialien (1471)
- 8 Zerstörungsfreie Prüfung (1320)
- 6 Materialchemie (1065)
- 6.1 Oberflächen- und Dünnschichtanalyse (368)
- 6.3 Strukturanalytik (337)
- 8.0 Abteilungsleitung und andere (330)
- 8.2 Zerstörungsfreie Prüfmethoden für das Bauwesen (328)
- 1.1 Anorganische Spurenanalytik (291)
- 1.2 Biophotonik (269)
- 8.4 Akustische und elektromagnetische Verfahren (259)
Paper des Monats
- ja (27)
Isotope analysis is a tool for material research. For example, it may provide information about the provenance of a sample or changes in dynamic systems. Here is presented optical spectroscopy as an analytical alternative to mass spectrometry for isotope quantification based on the isotopic shift of atoms and diatomic molecules.
Calcium isotope analysis can be an important tool for paleoclimate studies of the carbon cycle, as well in carbon capture technology, but its utility is limited by challenges using conventional mass spectrometry. We propose a new fast, precise, and high-throughput technology based on multiple complementary high-resolution spectroscopies analyzed by machine-learning.
The introduction of HR-CS-MAS instrumentation, as it is shown in Fig. 1, provides a new way for the determination of non-metals including fluorine via molecular absorption. We present a sensitive and fluorine-specific method for total fluorine determination in fifteen consume care products in which perfluordecalin were declared (nail polishes, eye shadows and body creams). After pyrohydrolytic digestion of samples, fluorine content was determined by GF-HR-CS-MAS. Calcium was used as a molecule forming element and the molecular absorption of calcium monofluoride (CaF) at the wavelength 606.440 nm was used for its quantification. No matrix effect was observed. Analytical signal depends only on the fluorine concentration and therefore pure sodium fluoride NaF was used as calibration standard. The use of zirconium oxide nanoparticles as permanent modifier improves the limit of detection (from 0.2 to 0.1 ng) and characteristic mass (from 0.10 to 0.05 ng) from a previous reported method. These results were also compared with ISE method (standard DIN 51-084) and no significant difference was found
Wie lässt sich die Herkunft von Rohstoffen, Lebensmitteln oder Umweltschadstoffen einfacher, schneller und kostengünstiger als mit bisherigen Methoden bestimmen?
Die Dissertation zeigt auf, dass man das grundlegende physikalische Prinzip einer Isotopverschiebung mit in Adlershof entwickelten Optik-Instrumenten für die Herkunftsbestimmung nutzen kann. Die entwickelte Methode ermöglicht es in Zukunft den Ursprung von Rohstoffen, Lebensmitteln oder Umweltschadstoffen kostengünstiger und wesentlich schneller bestimmen, als dies mit bisherigen Methoden möglich ist.
Kann man das grundlegende physikalische Prinzip einer Isotopieverschiebung mit einem Optik-Instrument für die Herkunftsbestimmung nutzen? Carlos Abad hat eine wegweisende Methode entwickelt, die es in Zukunft ermöglicht den Ursprung von Rohstoffen, Lebensmitteln oder Umweltschadstoffen kostengünstiger und wesentlich schneller bestimmen, als dies mit bisherigen Techniken möglich ist.
Analysis of stable isotopes has been used as proof of provenance of mineral and biological samples, to estimate a contamination source and to determine geological processes. This kind of analysis needs high accuracy and precision for reliable conclusions. Currently, stable isotope analysis is dominated by mass spectrometric techniques that are time consuming and expensive. Here we present a fast and low cost alternative for isotope analysis of boron and magnesium: high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS-GFMAS). Two stable isotope systems were evaluated separately: boron (10B:11B) and magnesium 24Mg:25Mg:26Mg). Their isotope amount ratios were estimated by monitoring their absorption spectra in-situ generated monohydrides. The molecular absorption spectrum of a XH molecule (X= B or Mg) with n isotopes would be a linear combination of n isotopologue spectra and the amount of each component (isotope) could be calculated by a multivariate regression (n= 2 and 3 for B and Mg respectively). For the Analysis of boron certified reference materials (CRM), the band 1→1 for the electronic transition X1Σ+ → A1Π was measured around wavelength 437.1 nm. Since boron has a Memory effect in graphite furnaces, a combination of 2 % (v/v) hydrogen gas in argon, 1 % trifluoromethane in argon, an acid solution of calcium chloride and mannitol as chemical modifiers were used during the BH vaporization at 2600 °C. Partial least square regression (PLS) for analysis of samples was applied. For this, a spectral library with different isotope ratios for PLS regression was created. Magnesium does not have memory effect. Therefore, only 2 % of hydrogen in argon as gas modifier during vaporization at 2500 °C was employed for analysis of magnesium CRM. Absorption spectra of MgH for the X2Σ→A2Π electronic transition (band 0→0) were recorded around wavelength 513.45 nm. A similar PLS procedure to the BH was applied. Results for B and Mg CRM are metrologically compatible with those reported by mass spectrometric methods. An accuracy of 0.08 ‰ for B and 0.1 ‰ Mg was obtained as the average deviation from the isotope CRM. Expanded uncertainties with a coverage factor of k = 2 range between 0.10 - 0.40 ‰.
Following fluorinated drugs by molecular absorption spectrometry – from cancer cells to body fluids
(2018)
Fluorine has been widely introduced into pharmaceutical drugs. Due to the high C-F bond strength, a single atom substitution with fluorine produces drastic desirable and tunable changes in the molecular properties. However, the clinical monitoring of these drugs is not straightforward.
Organofluorine compounds are elusive for a non-targeted analysis; a significant problem in fluorine determination is the lack of suitable detection techniques. Standard atomic absorption and emission spectrometers cannot access fluorine, because their resonance lines lie in the VUV spectral range below 100 nm. In the case of conventional inductively coupled argon plasmas (ICP), the plasma energy is too low to generate a significant population of excited fluorine atoms. Recently, our group introduces high-resolution continuum source absorption spectrometry (HR-CS MAS) as a new way for the indirect monitoring of fluorinated compounds. Main benefits of HR-CS-MAS includes low limits of detection, complete analyte recovery, simple to no sample preparation, and short time analysis.
Currently, two main high speed processes can be investigated: electromagnetic absorption and electromagnetic scattering. At the summer university of the School of Analytical Sciences Adlershof (SALSA-HU), a series of 5 articles were presented to ilustrate the potential of ultrafast spectroscopy, from IR band assignment to monitoring time resolved structural changes. First, by studying light absorption is possible to do assignment and interpretation of IR bands in small molecules and to study the influence of ligands or labeled molecules in protein structures. Second, by studying light scattering is possible to monitoring photoinduced structural changes in solid materials.
This presentation contains a study of photoinduced structural changes monitored by light scattering in condensed matter.
Boron presents two stable isotopes, 10B and 11B and due to their relatively large mass difference (~ 10%) isotope fractionation leads to considerable isotope amount ratio variations n(10B)/n(11B) in natural occurrence. These have been used as a proof of provenance of mineral and biological samples, to estimate a contamination source and to the determination of geological processes by erosion or subduction. Additionally, boron is employed in the nuclear industry due to the capability of its isotope 10B to thermal-neutron capture and therefore 10B enriched boric acid solutions are used in the cooling system of thermonuclear facilities and in the alloying of steel and carbides for protective shielding. Usually, isotope ratio variations are determined by mass spectroscopic methods.
Here an alternative faster and low cost method for isotope ratio determination is proposed: high-resolution continuum source molecular absorption spectrometry (HR-CS-MAS). Boron isotope amount ratios have been determined by monitoring the absorption spectrum of boron monohydride (BH) in graphite furnace HR-CS-MAS. Bands (0→0) and (1→1) for the electronic transition X1Σ+ → A1Π were evaluated around wavelengths 433.1 nm and 437.1 nm respectively. Partial least square regression (PLS) for analysis of samples and reference materials were applied. For this, a spectral library with different isotopes ratios for PLS regression was built. Results obtained around the 433.1 nm and 437.1 nm spectral regions are metrologically compatible with those reported by mass spectrometric methods. Moreover, a precision and accuracy of the method of ± 0.5 ‰ for the evaluated spectral region around 437.1 nm is reported here. This accuracy and precision is comparable with those obtained by thermal ionization mass spectrometry (TIMS) and multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS) for boron isotope ratio measurements.
Analysis of stable isotopes has been used as proof of provenance of mineral and biological samples, to estimate a contamination source and to determine geological processes. This kind of analysis needs high accuracy and precision for reliable conclusions. Currently, stable isotope analysis is dominated by mass spectrometric techniques that are time consuming and expensive. Here we present a fast and low cost alternative for isotope analysis of boron and magnesium: high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS-GFMAS). Two stable isotope systems were evaluated separately: boron (10B:11B) and magnesium (24Mg:25Mg:26Mg). Their isotope amount ratios were estimated by monitoring their absorption spectra in-situ generated monohydrides. The molecular absorption spectrum of a XH molecule (X= B or Mg) with n isotopes would be a linear combination of n isotopologue spectra and the amount of each component (isotope) could be calculated by a multivariate regression (n= 2 and 3 for B and Mg respectively). For the analysis of boron certified reference materials (CRM), the band 1→1 for the electronic transition X1Σ+ → A1Π was measured around wavelength 437.1 nm. Since boron has a memory effect in graphite furnaces, a combination of 2 % (v/v) hydrogen gas in argon, 1 % trifluoromethane in argon, an acid solution of calcium chloride and mannitol as chemical modifiers were used during the BH vaporization at 2600 °C. Partial least square regression (PLS) for analysis of samples was applied. For this, a spectral library with different isotope ratios for PLS regression was created. Magnesium does not have memory effect. Therefore, only 2 % of hydrogen in argon as gas modifier during vaporization at 2500 °C was employed for analysis of magnesium CRM. Absorption spectra of MgH for the X2Σ→A2Π electronic transition (band 0→0) were recorded around wavelength 513.45 nm. A similar PLS procedure to the BH was applied. Results for B and Mg CRM are metrologically compatible with those reported by mass spectrometric methods. An accuracy of 0.08 ‰ for B and 0.1 ‰ Mg was obtained as the average deviation from the isotope CRM. Expanded uncertainties with a coverage factor of k = 2 range between 0.10 - 0.40 ‰.