Analysis of Coffee Aroma Compounds by Headspace Solid-Phase Microextraction (SPME) GC-MS with the JMS Q1500GC Master-Quad GC-MS System The composition of volatiles from freshly ground roasted coffee is complex, with hundreds of chemical compounds contributing to the aroma. Headspace solid-phase microextraction was used to sample volatiles from five different coffees for analysis by GC-MS. Chemometric analysis revealed specific differences between coffees from different origins and different preparations. May 5, 2021 Application Note, GC Single-Quad MS, Mass Spectrometry (MS) 0 Comment Read More >>
Quantifying Power Flow Processes Mediated by Spin Currents The power flow process mediated by spin current in the bilayer device consisting of ferromagnetic metal (FM) and nonmagnetic metal (NM) layers is examined by realizing experimental evaluations for each process from the microwave absorption to electromotive force (EMF) output. The absorption power by ferromagnetic resonance (FMR) of the thin FM layer during the EMF output is directly measured in operando using an antenna probe system. The transfer efficiency of the absorption power into the NM layer by spin pumping is estimated from strict linewidth evaluation of EMF spectra. The maximum transfer efficiency of the spin pumping power to the external load via the inverse spin Hall effect is determined to be 4.2 × 10–8 under 162 mW microwave irradiation using an analysis model assuming a parallel circuit. The main factors reducing the efficiency are found to be low resistivity of the NM layer and the interface loss. These quantifications are important as a first step to consider the efficient transfer of spin energy mediated by spin currents. April 30, 2021 Electron Spin Resonance (ESR), ESR Peer-Reviewed Articles 0 Comment Read More >>
Integrated Analysis of GC-HRTOFMS Data Using Hard and Soft Ionization to Identify Trace Impurities in Fine Chemicals Non-targeted analysis of complex mixtures by GC-HRMS should make use of all of the available data to identify unknowns. An automated data analysis software package combining chromatographic deconvolution with integrated analysis of high-resolution mass spectra for electron ionization (EI) and soft ionization measurements is applied to the identification of trace impurities in a fine chemical (triphenylphosphine). April 28, 2021 AccuTOF™ GC, Application Note, Mass Spectrometry (MS), msFineAnalysis 0 Comment Read More >>
Selective detection of active pharmaceutical ingredients in tablet formulations using solid-state NMR spectroscopy Highlights: • Selective detection of 1H signals of API in a tablet formulation is proposed. • 1H signals of excipients are suppressed. • 1H signals in the vicinity of nuclei (here 14N) which only appear in API are excited. • 1H{14N} magnetization is diffused to 1Hs in API crystals by RFDR recoupling. March 24, 2021 NMR Peer-Reviewed Articles, Nuclear Magnetic Resonance (NMR) 0 Comment Read More >>
13c13c-spin-coupling-constants-in-crystalline-13c-labeled-saccharides-conformational-effects-interrogated-by-solid-state-13c-nmr-spectroscopy This experimental approach allows direct correlation of JCC values with specific molecular conformations since, in crystalline samples, molecular conformation is essentially static and can be determined by X-ray crystallography. March 24, 2021 NMR Peer-Reviewed Articles, Nuclear Magnetic Resonance (NMR) 0 Comment Read More >>
Precise 1H- and 13C-NMR reassignment of dehydrocrebanine by 10-mg INADEQUATE and in silico analysis: With an alert for its toxicity A collaborative paper was published in Tetrahedron. The INADEQUATE spectrum discussed in this research was obtained using a cryogenic probe (UltraCOOL probe) in liquid helium in a JEOL 800 MHz spectrometer (JNM-ECZ800R). March 24, 2021 NMR Peer-Reviewed Articles, Nuclear Magnetic Resonance (NMR) 0 Comment Read More >>
Dynamic Transformation Between Covalent Organic Frameworks And Discrete Organic Cages We propose a dynamic covalent chemistry (DCC)-induced linker exchange strategy for the structural transformation between covalent organic frameworks (COFs) and cages for the first time. Studies have shown that the COF-to-cage and cage-to-COF transformations were realized by using borate bonds and imine bonds, respectively, as linkages. Self-sorting experiments suggested that borate cages and imine COFs are thermodynamic minimum compounds. This research builds a bridge between discrete and polymeric organic scaffolds and broadens the knowledge of chemistry and materials for porous materials science. March 24, 2021 NMR Peer-Reviewed Articles, Nuclear Magnetic Resonance (NMR) 0 Comment Read More >>
MALDI imaging brochure Advanced statistical analysis of MALDI MS imaging data required by SpiralTOF-plus while taking full advantage of its high mass-resolving power. March 19, 2021 Application Note, MALDI Imaging, Mass Spectrometry (MS), Product Brochures, SpiralTOF™ 0 Comment Read More >>
Azoxystrobin amine: A novel azoxystrobin degradation product from Bacillus licheniformis strain TAB7 Azoxystrobin (AZ) is a broad-spectrum synthetic fungicide widely used in agriculture globally. However, there are concerns about its fate and effects in the environment. It is reportedly transformed into azoxystrobin acid as a major metabolite by environmental microorganisms. Bacillus licheniformis strain TAB7 is used as a compost deodorant in commercial compost and has been found to degrade some phenolic and agrochemicals compounds. In this article, we report its ability to degrade azoxystrobin by novel degradation pathway. Biotransformation analysis followed by identification by electrospray ionization-mass spectrometry (MS), high-resolution MS, and nuclear magnetic resonance spectroscopy identified methyl (E)-3-amino-2-(2-((6-(2-cyanophenoxy)pyrimidin-4-yl)oxy)phenyl)acrylate, or (E)-azoxystrobin amine in short, and (Z) isomers of AZ and azoxystrobin amine as the metabolites of (E)-AZ by TAB7. Bioassay testing using Magnaporthe oryzae showed that although 40 μg/mL of (E)-AZ inhibited 59.5 ± 3.5% of the electron transfer activity between mitochondrial Complexes I and III in M. oryzae, the same concentration of (E)-azoxystrobin amine inhibited only 36.7 ± 15.1% of the activity, and a concentration of 80 μg/mL was needed for an inhibition rate of 56.8 ± 7.4%, suggesting that (E)-azoxystrobin amine is less toxic than the parent compound. To our knowledge, this is the first study identifying azoxystrobin amine as a less-toxic metabolite from bacterial AZ degradation and reporting on the enzymatic isomerization of (E)-AZ to (Z)-AZ, to some extent, by TAB7. Although the fate of AZ in the soil microcosm supplemented with TAB7 will be needed, our findings broaden our knowledge of possible AZ biotransformation products. March 16, 2021 NMR Peer-Reviewed Articles, Nuclear Magnetic Resonance (NMR) 0 Comment Read More >>
Understanding hydrogen-bonding structures of molecular crystals via electron and NMR nanocrystallography Understanding hydrogen-bonding networks in nanocrystals and microcrystals that are too small for X-ray diffractometry is a challenge. Although electron diffraction (ED) or electron 3D crystallography are applicable to determining the structures of such nanocrystals owing to their strong scattering power, these techniques still lead to ambiguities in the hydrogen atom positions and misassignments of atoms with similar atomic numbers such as carbon, nitrogen, and oxygen. Here, we propose a technique combining ED, solid-state NMR (SSNMR), and first-principles quantum calculations to overcome these limitations. The rotational ED method is first used to determine the positions of the non-hydrogen atoms, and SSNMR is then applied to ascertain the hydrogen atom positions and assign the carbon, nitrogen, and oxygen atoms via the NMR signals for 1H, 13C, 14N, and 15N with the aid of quantum computations. This approach elucidates the hydrogen-bonding networks in L-histidine and cimetidine form B whose structure was previously unknown. March 16, 2021 NMR Peer-Reviewed Articles, Nuclear Magnetic Resonance (NMR) 0 Comment Read More >>