Mass spectrometer high resolution

All have molecular weights of 226 to the nearest integer (C = 12, H = 1, S = 32), but the exact molecular weights differ slightly. A resolution of 2500 is necessary to separate molecules 1, 2 and 3 but 75,000 is required to separate molecule 4 from molecule 3 which explains why high resolution mass spectrometers are sdiiglit. 

Exact Mass Differences. If the exact mass of the parent or fragment ions are ascertained with a high-resolution mass spectrometer, this relationship is often useful for combinations of C, H, N, and O (Table 1.15b) ... 

The four-sector mass spectrometer is the ultimate in MS-MS instrumentation and consists of two high-resolution mass spectrometers in series. The strength of these instruments is in terms of their high-mass and high-resolution capabilities for both precursor-ion selection and product-ion analysis. Their cost, however, precludes their primary use for LC-MS and therefore they will not be considered any further here [12]. 

High-resolution mass spectrometers have been used to obtain electrospray spectra and have the added advantage that they allow the direct determination of the charge state of the ions being observed, e.g. if the apparent separation of the and isotopic contributions is 0.1 Da, the charge state is 10, while if it is 0.05 Da, the charge state is 20, etc. 

High-resolution mass spectrometer A mass spectrometer capable of high resolution and measuring m/z ratios with high accuracy to enable the atomic composition of an ion to be determined. 

The nature of water residue analysis has changed dramatically over the past 60 years. Advances in SPE media have made the isolation of hard to extract residues more attainable. The use of specific and sensitive instrumentation as in HPLC/MS/MS has even precluded the need for extraction in many cases, since the samples can be directly analyzed as they are received from the Held. The future holds even more improvements in sensitivity with rugged new API interfaces and high-resolution mass spectrometers that will dramatically increase the specificity of detection and ease of analysis. 

Retro-ene reaction of an N-allylsilanamine under flash vacuum thermolysis (FVT) conditions. The iminosilane has been identified not only by reaction with the trapping agent /-butyl alcohol, but also directly by coupling the oven with a high-resolution mass spectrometer.7... 

Data were obtained anew on a high resolution mass spectrometer by direct inlet probe at 70 eV (Ref. 13). 

Mamyrin, B. A. Karataev, V. I. Shmikk, D. V. Zagulin, V. A. Mass reflectron New nonmagnetic time-of-flight high-resolution mass spectrometer. Zh. Eksp. Teor. Fiz. 1973, 64, 82-89. 

MAT-90 high-mass-high-resolution mass spectrometer... 

Nier, A.O. The Development of a High Resolution Mass Spectrometer a Reminiscence. J. Am. Soc. Mass Spectrom. 1991,2,447-452. 

The powerful technique of coupling a computer to a high-resolution mass spectrometer has been used to analyze air pollutants. Both particulate matter and gases can be scanned for up to 300 pollutants. Only stable compounds will be detected by this method, because the samples are concentrated before analysis. 

The development of lasers has opened up several new techniques for monitoring pollutants in the atmosphere. Sensitivities down to the parts-per-billion range are claimed, and continuous monitoring is possible. The photoionization mass spectrometer has been developed as a sensitive detector for fi radicals in the gas phase. A high-resolution mass spectrometer coupled to a computer is capable of detecting up to 300 compounds in air, both in particulate form and in the gas phase. 

In this chapter we focus primarily on calibration of LC-MS where the mass spectrometer is operating at unit resolution, resolution that is sufficient to separate two peaks one mass unit apart. This kind of low-resolution mass filter covers almost 90 percent of the instruments commonly used for qualitative and/or quantitative analysis of small molecules. Batch-to-batch qualification testing of the instrument is also described. For the calibration of high-resolution mass spectrometers such as magnetic sector, TOF, or FTICR coupled with liquid chromatography, readers are referred to specific publications. 

Mass spectral (MS) determinations were performed on a Kratos MS 80 high-resolution mass spectrometer as described previously (3,13). 

The separation of ions in the mass spectrometer is caused by the action of a magnetic field At increasing mass numbers, the distance between the M and the M+1 peaks becomes smaller. The usual instruments provide a good resolution in the region up to 600-700 mass units. Special, high-resolution, mass spectrometers completely remove this limitation, and the only one remaining appears to be the volatility factor. 

Yinon H.G. Boettger, Modification of a High-Resolution Mass Spectrometer for Negative Ionization , IntJMassSpectromlonPhys 10 (2) (1972) 73) M. Aubar J.T. Moseley, USP... 

The mass spectra were determined on a LKB 900U Model GC/MS instrument. The elemental analysis was obtained by a VG-model ZAB double focusing high resolution mass spectrometer. The infrared spectra were measured on a Perkin-Elmer 567 spectrophotometer and with a chromatographic infrared analyzer (CIRA 101). The ultraviolet spectra were determined by a UV-visible spectrophotometer (Hitachi Perkin Elmer Model 139). 

The authors would like to acknowledge the Electric Power Research Institute for support of this work under Contract RP1676-3, Dr. J. Appleby for helpful discussion, Dr. D. Thomas for mass spectra, Mr. L. Cary for NMR spectra and Professor J. C. Cook for elemental analysis by a double focusing high resolution mass spectrometer. 

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