Related Articles

• ¹⁴N decoupled ¹H–¹⁹F HOESY with ROYALPROBE™ HFX_NM190012E

  Fluorine and nitrogen containing organic compounds are often found in a variety of fields such as pharmaceutical and material sciences. Such compounds show unique properties based on their conformations and orientations, which are often induced by hydrogen bonds between N-H and F atoms. Therefore, analysis of molecular conformations and inter-molecular interactions are important. Here, we report 14N decoupled 1H–19F HOESY (hetero nuclear NOE) for fluroinated benzanilide (1) as a demonstration.
• Visualizing fragmentation channels of polyethylene oxide with different end groups using the JMS-S3000 SpiralTOFTM with TOF–TOF option

  Tandem mass spectrometry is a powerful tool for polymer characterization. It can obtain information about polymer end groups, repeating structures (linear, cyclic, or branched), and copolymerization. High-energy collision–induced dissociation (HE-CID) is a fragmentation method that is available only in tandem time-of-flight mass spectrometry (TOF–TOF). The informative fragmentation channels, which are difficult to observe with commonly used low-energy CID, are often observable in HE-CID spectra. In MSTips 270, we proposed a method to visualize this abundant structural information and enable intuitive analysis using the “Remainders of KM” (RKM) plot method. In this report, we applied the method to analyze polyethylene oxide (PEO) with different end groups.
• Analysis of Acrylamide in Food by LC/Time-of-Flight Mass Spectrometry

  Acrylamide has been shown to cause cancer in animal studies. It has also been shown to cause nerve damage in people who have been exposed to very high levels at work. In April 2002 the Swedish National Food Authority reported the presence of elevated levels of acrylamide in certain types of food processed at high temperatures. Since then, acrylamide has been found in a range of cooked and heat-processed foods in many countries including the United States [1]. In order to assess acrylamide risk to humans, food levels need to be measured accurately. This prompts the need for development of analytical methods for acrylamide analysis. The US Food and Drug Administration has published an LC/MS/MS method for acrylamide [2]. Due to the low molecular weight of acrylamide, GC/MS has also been used for its analysis [3, 4]. However, GC/MS requires time-consuming derivatization. Here, we describe a simple and rapid LC/Time-of-flight MS method with accurate mass measurement and “in-source CID” fragmentation for acrylamide analysis.
• 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.
• MS imaging for visualizing synthetic polymers combined with KMD - MSTips - 306

  In this report, we have combined this method with the Kendrick Mass Defect (KMD) method to effectively visualize polymer series mixtures.
• Direct Analysis of Drugs in Pills and Capsules with No Sample Preparation

  The AccuTOF™ equipped with Direct Analysis in Real Time (DART™) is capable of analyzing drugs in pills and capsules with no sample preparation. In most cases, the pill can simply be placed in front of the DART and the active ingredients can be detected within seconds. This application note shows a wide variety of pills that have been analyzed by using DART. The examples include prescription drugs, over-the-counter medicines, and illicit drugs that were confiscated by a law-enforcement agency.