Analytical Instrument Documents

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.

All mass spectrometers combine ion formation, mass analysis, and ion detection. This discussion is concerned with how various mass analyzers are used to separate ions according to their massto- charge ratio. Each mass analyzer has its own special characteristics and applications and its own benefits and limitations. The choice of mass analyzer should be based upon the application, cost, and performance desired. There is no ideal mass analyzer that is good for all applications. For an excellent and more complete discussion of mass analyzers, see "The Ideal Mass Analyzer: Fact or Fiction?" (Curt Brunnee, Int. J. Mass Spectrom. Ion Proc. 76 (1987), 125-237.

A mass spectrometer works by using magnetic and electric fields to exert forces on charged particles (ions) in a vacuum. Therefore, a compound must be charged or ionized to be analyzed by a mass spectrometer. Furthermore, the ions must be introduced in the gas phase into the vacuum system of the mass spectrometer. This is easily done for gaseous or heat-volatile samples. However, many (thermally labile) analytes decompose upon heating. These kinds of samples require either desorption or desolvation methods if they are to be analyzed by mass spectrometry. Although ionization and desorption/desolvation are usually separate processes, the term "ionization method" is commonly used to refer to both ionization and desorption (or desolvation) methods. The choice of ionization method depends on the nature of the sample and the type of information required from the analysis. So-called 'soft ionization' methods such as field desorption and electrospray ionization tend to produce mass spectra with little or no fragment-ion content.

Double-focusing magnetic sector mass spectrometers provide high sensitivity, high resolution, and a reproducibility that is unmatched in any other kind of mass analyzer.

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.

The JMS-S3000 “SpiralTOF™” is a MALDI-TOFMS that incorporates an innovative SpiralTOF ion optics system. This system is available with a TOF-TOF option that can acquire high-energy collision-induced dissociation (CID) product ion spectra for monoisotopically selected precursor ions. In this work, we analyzed Poly Methyl Methacrylate (PMMA) shown in Fig. 1 by using the JMS-S3000 SpiralTOF with the TOF-TOF option. The resulting high-energy CID data was then processed using the Polymerix™ (Sierra Analytics, Inc., http://massspec. com/) analysis software.

Various kinds of additives are used in a polymer, such as an antioxidant, a light stabilizer, and an ultraviolet absorber. Because a polymer’s properties depend on the additives in the raw material, it is important to understand these additives. Matrix-assistance laser desorption/ ionization time-of-flight mass spectrometer (MALDI-TOFMS) JMS-S3000 SpiralTOF™ is widely used in polymer analysis. High-energy collision–induced dissociation (HE-CID) measurement with the TOF-TOF option is also useful in analyzing the structures of additives. SpiralTOF™ can achieve a high precursor ion selection with a revolution of 17 m. Fragmentation derived from HE-CID can be observed only due to the ions from post-source decay (PSD), these fragment ions can be eliminated by the four electrostatic sectors that constitute the spiral trajectory. In this Applications Note, we report on polymer structural analysis by compare fragmentation patterns in the product ion spectra of IRGANOX 1076 M+・ and [M+Na]+.

The JMS-S3000 SpiralTOF™ is a MALDI-TOF MS that uses an innovative spiral ion optical system to achieve the highest resolution currently available for a MALDI instrument. Additionally, this system can be equipped with a TOF-TOF option that can acquire high-energy collisioninduced dissociation (HE-CID) product ion spectra for monoisotopically selected precursor ions. The resulting HE-CID product ion spectra provide detailed structural information about compounds like triglycerides by means of charge-remote fragmentation (CRF).1 Tristearin is a triglyceride found in fats that consists of three stearic acid moieties (Fig. 1). In this work, we report the structural analysis of tristearin by using the HE-CID capabilities of the SpiralTOF-TOF.

The JMS-S3000 “SpiralTOF™” is a MALDI-TOF MS that uses an innovative spiral ion optical system to achieve the highest resolution currently available for a MALDI instrument. Additionally, this system can be equipped with a TOF-TOF option that can acquire high-energy collisioninduced dissociation (HE-CID) product ion spectra for monoisotopically selected precursor ions. The resulting HE-CID product ion spectra provide detailed structural information about compounds like triglycerides by means of charge-remote fragmentation (CRF). In this work, we report the structural analysis of triolein, a triglyceride that contains 3 oleic acid moieties (Fig. 1), by using HE-CID capabilities of the SpiralTOF-TOF.

In previous work, we showed that the JEOL SpiralTOFTOF system’s high-energy collision-induced dissociation (HE-CID) is useful for the structural analysis of triglycerides. The resulting HE-CID mass spectra provided detailed information about the fatty acid moieties such as the positions of double bonds, branching, hydroxylation, and oxidation by means of charge-remote fragmentation (CRF). In this work, we report the structural analysis of oxidized triglycerides by HE-CID using the SpiralTOFTOF.