Related Articles

• 2D homonuclear correlation 1H solid-state NMR by wPMLG_NM200011E

  Multidimensional correlation NMR spectroscopies, which provides inter-nuclear proximity/connectivity, play a crucial role to probe the atomic resolution structures. Especially, 1H-1H homonuclear correlation spectroscopy is quite useful source of information because of high abundance (>99%) and gyromagnetic ratio, thus resulting in strong inter nuclear interactions. Thanks to the development of high resolution 1H solid-state NMR, now it is feasible to observe 1H-1H correlation high resolution solid-state NMR [1]. There are two distinctive categories; 1) single quantum (SQ)/SQ correlation and 2) double quantum (DQ)/SQ correlations. In this note we introduce 2D 1H SQ/ 1H SQ and 1H DQ/ 1H SQ correlation spectroscopy to probe the internuclear proximity using high-resolution 1H solid-state NMR techniques.
• Experimental set-up of high-resolution 1H solid-state NMR by wPMLG_NM200010E

  1H, in principle, is very useful nucleus to investigate atomic-resolution structures and dynamics due to its high abundance (>99%) and gyromagnetic ratio (600 MHz at 14.1T). In fact 1H is the first choice of nucleus in solution NMR. On the other hand, 1H NMR of rigid solids is much less common. This is because 1H solid-state NMR gives very broad (~50 kHz) and featureless spectra (Fig 1a) due to strong 1H-1H dipolar coupling, which is dynamically averaged out in solution. Magic angle spinning (MAS) removes the broadening to the first order, but is not enough to achieve high resolution 1H NMR at moderate MAS rate (Fig 1b). Tremendous efforts were made to overcome this issue from the early dates of solid-state NMR towards high-resolution 1H NMR [1]. Most of them combine MAS with sophisticated 1H pulses which is dubbed CRAMPS (combined rotation and multiple pulse spectroscopy). Nowadays very fast MAS > 60 kHz can be used to achieve high-resolution 1H solid-state NMR (Fig 1c) [2]. However, the traditional CRAMPS is still useful as that can be performed with very conventional solid-state NMR equipment, for example 4 mm MAS probe with a 400 MHz spectrometer. Moreover, wPMLG at moderate MAS rate often overwhelms fast MAS in terms of resolution. In this note, we will describe tutorial guidance to optimize experimental parameters for CRAMPS.
• Analysis of duct tapes by thermal desorption and pyrolysis mass spectrometry and X-ray-fluorescence spectroscopy

  The identification of pressure-sensitive tapes such as duct tape and electrical tape is an important forensic application. Here we show the application of thermal desorption and pyrolysis combined with Direct Analysis in Real Time (DART) mass spectrometry to distinguish between manufacturers and brands of duct tapes. X-ray fluorescence (XRF) provides complementary information about the atomic composition of the different tapes.
• Analysis of Organic Thin Films by the Laser Desorption/Ionization Method Using the JMS-S3000 “SpiralTOF”

  Laser Desorption/ Ionization-Time of Flight Mass Spectrometry (LDI-TOFMS) is generally used for analysis of organic compounds because this technique generates little fragmentation of molecular ions at ionization. It makes possible to obtain information on molecular weights and molecular structures in organic compounds. In particular, a technique which uses the matrix compounds for enhancing ionization efficiency is well known as Matrix-Assisted Laser Desorption/ Ionization-Time of Flight Mass Spectrometry (MALDI-TOFMS). This technique is widely used in the bio markets owing to its capability of ionizing proteins and peptides with the molecular weights of several thousands to several hundreds of thousands. The MALDI-TOFMS is also utilized for analysis of synthetic polymers. In many cases, LDI-TOFMS and MALDI-TOFMS have been used to estimate the molecular weights of organic compounds in solution. But very recently, techniques of imaging mass spectrometry, which controls the laser irradiation position by two-dimensional scan to acquire mass spectra for visualizing localization of chemical compounds with specific molecular weights, have been improved. The application of this innovative technique is increasingly spreading in the bio markets. The technology of Imaging Mass Spectrometry has been advancing for analyzing biological tissue sections, but in the future, it is expected to develop toward the material science markets. It is noted that various surface analytical techniques are already available in the material science markets. In order to study the advantages of LDI-TOFMS as one of effective surface analysis tools, it is essential to consider the complementary analysis of LDI-TOFMS with the existing surface analytical techniques. In this article, the advantages of using LDI-TOFMS for analyzing organic lightemitting diode material thin films, in accordance with comparison with Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS), X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy/Energy-Dispersive X-Ray Spectroscopy (SEM/EDS), have been studied. In addition, since LDI-TOFMS is a destructive analytical technique, the influence on the sample surface caused by LDI-TOFMS was also examined.
• NMR Innovation: A Manufacturer’s Perspective on Analytical Advances and New Applications

  Looking back, NMR spectroscopy has been in use as a research tool and under constant development for almost 80 years. Some principles of magnetic resonance were initially described by Isidor Isaac Rabi of Columbia University in 1938. With further fundamental research being done in the late 1930s and early ’40s, the official birth of the technique is generally accepted to have been in 1946 and is attributed to Edward M. Purcell and Felix Bloch. Both were honored with the Nobel Prize for Physics in 1952 for the discovery of NMR spectroscopy. Dr. Ray Freeman, one of the pioneers of NMR applications technology, has created a resource for further reading on the history of both the science and development of NMR technology.
• JEOL Case Study: Lowell NMR

  University of Massachusetts Lowell’s NMR Spectroscopy Facility Manager, Wendy Gavin, discusses the importance of an NMR vendor that supports the constant challenge to be innovative. With over 13 years spent working in industry, 11 in a large pharmaceutical company, it is safe to say that Wendy Gavin knows the secret to successful nuclear magnetic resonance (NMR). Wendy has worked at the university for over six years and, as well as being the NMR Core Research Facility Manager, she also manages the University’s Analytical Chemistry lab. Her experience working in industry has provided unique insights into a customer’s requirements and enables her to ensure that the NMR facility at the University of Massachusetts Lowell is providing high quality data. Here, she explains the difference it makes to have an instrumentation vendor that goes the extra mile to support all users.