Examining detection sensitivity of EI-FI and PI ion sources using nitrogen as a GC carrier gas MSTips 299 In this work, we compare sensitivity levels when using the combination EI/FI and EI/PI ion sources when He and N2 are used as the GC carrier gas. May 17, 2022 AccuTOF™ GC, Application Note, Essay / Tutorial, Introduction, Mass Spectrometry (MS) 0 Comment Read More >>
Hysteresis-Suppressed Reversible Oxygen-Redox Cathodes for Sodium-Ion Batteries This research demonstrates the effect of Li and Ni co-doping in P2-type layered materials and suggests a new strategy of using Mn-rich cathode materials. May 17, 2022 NMR Peer-Reviewed Articles, Nuclear Magnetic Resonance (NMR) 0 Comment Read More >>
Practical guides for 1H detected solid-state NMR under fast MAS for small molecules This primer article introduces a practical guide for setting up 1H detection solid-state NMR experiments under fast MAS conditions for small molecules. May 16, 2022 NMR Peer-Reviewed Articles, Nuclear Magnetic Resonance (NMR) 0 Comment Read More >>
Polymeric Materials Analysis by JEOL Mass Spectrometers - A Guidebook In this guidebook, we will introduce polymeric material analysis solutions that make full use of JEOL's high-performance mass spectrometers. April 22, 2022 Mass Spectrometry (MS), Product Brochures (MS) 0 Comment Read More >>
JMS-S3000 SpiralTOF™-plus Product Brochure The JMS-S3000 SpiralTOF™-plus Ultra-High Mass Resolution MALDI-TOFMS System time-of-flight optics design utilizes a figure-eight ion trajectory to allow a 17m flight path to fit in an extremely small console. February 15, 2022 Application Note, MALDI SpiralTOF™, MALDI SpiralTOF™-TOF, Mass Spectrometry (MS), Product Brochures (MS) 0 Comment Read More >>
Solid-state MAS NMR at ultra low temperature of hydrated alanine doped with DNP radicals Magic angle spinning (MAS) nuclear magnetic resonance (NMR) experiments at ultra low temperature (ULT) ( 100 K) have demonstrated clear benefits for obtaining large signal sensitivity gain and probing spin dynamics phenomena at ULT. ULT NMR is furthermore a highly promising platform for solid-state dynamic nuclear polarization (DNP). However, ULT NMR is not widely used, given limited availability of such instrumentation from commercial sources. In this paper, we present a comprehensive study of hydrated [U-C]alanine, a standard bio-solid sample, from the first commercial 14.1 Tesla NMR spectrometer equipped with a closed-cycle helium ULT-MAS system. The closed-cycle helium MAS system provides precise temperature control from 25 K to 100 K and stable MAS from 1.5 kHz to 12 kHz. The C CP-MAS NMR of [U-C]alanine showed 400% signal gain at 28 K compared with at 100 K. The large sensitivity gain results from the Boltzmann factor, radio frequency circuitry quality factor improvement, and the suppression of its methyl group rotation at ULT. We further observed that the addition of organic biradicals widely used for solid-state DNP significantly shortens the H T1 spin lattice relaxation time at ULT, without further broadening the C spectral linewidth compared to at 90 K. The mechanism of H T1 shortening is dominated by the two-electron-one-nucleus triple flip transition underlying the Cross Effect mechanism, widely relied upon to drive solid-state DNP. Our experimental observations suggest that the prospects of MAS NMR and DNP under ULT conditions established with a closed-cycle helium MAS system are bright. January 24, 2022 NMR Peer-Reviewed Articles, Nuclear Magnetic Resonance (NMR) 0 Comment Read More >>
Facile Material Design Concept for Co-Free Lithium Excess Nickel-Manganese Oxide as High-Capacity Positive Electrode Material High-capacity Li1+x(Ni0.3Mn0.7)1-xO2, (0 < x < 1/3) samples were synthesized by the coprecipitation–calcination method. Both electrochemical cycle and high-rate performances were drastically improved by selecting an N2 atmosphere as final calcination. Scanning transmission electron microscopy—energy dispersive X-ray spectroscopy analysis showed that the sample calcined in an N2 atmosphere had a more homogeneous transition metal distribution into primary particles than that calcined in air. The solid-state 7Li nuclear magnetic resonance data showed that electrochemically inactive domains were only diminished for the sample calcined in an N2 atmosphere after electrochemical activation. X-ray Rietveld analysis revealed that the suitable transition metal distribution and content of the samples were different from those of typical layered rock-salt materials. Only that calcined in an N2 atmosphere had no spinel formation during charging and no oxide ion insertion reaction during discharging. No positive Co substitution effect was observed under the optimized preparation conditions. At the 100th cycle, the discharge capacity was 216 mAh g−1, which corresponds to 87% of the initial capacity (251 mAh g−1) at optimizing synthetic condition. December 13, 2021 NMR Peer-Reviewed Articles, Nuclear Magnetic Resonance (NMR) 0 Comment Read More >>
Analysis of Degraded Polymethyl Methacrylate by UV Irradiation - MSTips 324 Polymers can be degraded by the effects of light, oxygen, heat, etc. so it is important to understand how the polymer structures change during degradation. Pyrolysis gas chromatograph quadrupole mass spectrometer (Py-GC-QMS) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOFMS) are powerful tools for analyzing polymeric materials. Py-GC-QMS is a method that instantaneously heats a sample with a pyrolyzer and then analyzes the pyrolysis products by GC-MS. Since most of the pyrolysis products are related to monomers and dimers, this technique allows for easy identification of the polymer substructures which is useful for identifying changes to the polymer when degradation occurs. MALDI-TOFMS involves a soft ionization technique that can directly ionize and analyze the intact polymer molecules and often produces singly-charged ions even for high molecular weight compounds. As a result, the m/z axis of the mass spectrum is equal to the mass of the ions, thus making it easy to interpret polymer distributions. Additionally, when MALDI is used with a high-resolution TOFMS, the accurate mass of each ion in the polymer series can be used to calculate their elemental compositions. Moreover, the molecular weight distribution of polymers can be calculated from the ion intensity distribution. In this work, we used Py-GC-QMS and high-resolution MALDI-TOFMS to evaluate the effects of UV irradiation on polymethyl methacrylate (PMMA). December 13, 2021 Application Note, GC Single-Quad MS, MALDI SpiralTOF™, Mass Spectrometry (MS) 0 Comment Read More >>
A comparative study of the photocatalytic and optical properties of spinel-type titanates: A report for spinel sodium titanate The recent discovery of Na3LiTi5O12 (NTO), which possesses spinel symmetry (, #227) with the 8a site occupied by Na, has enabled investigations into the effect of the 8a-site cation on the physical properties of spinel titanates. Hence, in this study, the optical and photocatalytic properties of NTO were investigated and compared with those of spinel Li4Ti5O12 (LTO) and rutile TiO2. The bandgaps were estimated theoretically using hybrid density functional theory and experimentally using the ultraviolet–visible spectroscopy, and the obtained results were similar for both methods and spinel titanates. The valence- and conduction-band components of the spinel-type titanates were similar to those of other titanium oxides, and both NTO and LTO exhibited photocatalytic activity for sacrificial H2 evolution from water. However, although they have similar band structures and optical properties, the NTO photocatalytic activity was clearly lower than that of LTO. This can be attributed to the surface roughness and ease of defect formation in the NTO system, which hindered charge separation. These results indicate that the optical properties of spinel-type titanates can be tuned by replacing the cations at the 8a sites. December 13, 2021 NMR Peer-Reviewed Articles, Nuclear Magnetic Resonance (NMR) 0 Comment Read More >>
Integrated Data Analysis Making Use of the Total Information from Gas Chromatography and High-Resolution Time-of-Flight Mass Spectrometry to Identify Qualitative Differences Between Two Whisky Samples Analysis of complex mixtures with gas chromatography coupled with high-resolution time-of-flight mass spectrometry (GC-HRTOFMS) can produce a large amount of data. A new software program was recently reported that integrates all of the available mass spectrometric information from GC-HRTOFMS analysis into a concise report. New capabilities have now been added to the software to incorporate retention index data and to identify differences between two samples. December 13, 2021 Mass Spectrometry (MS), MS Peer-Reviewed Articles 0 Comment Read More >>