Mass spectrometer, types

Complexity of Samples to Be Examined and Mass Spectrometer Type... 

Specific surface areas of the catalysts used were determined by nitrogen adsorption (77.4 K) employing BET method via Sorptomatic 1900 (Carlo-Erba). X-ray difiraction (XRD) patterns of powdered catalysts were carried out on a Siemens D500 (0 / 20) dififactometer with Cu K monochromatic radiation. For the temperature-programmed desorption (TPD) experiments the catalyst (0.3 g) was pre-treated at diflferent temperatures (100-700 °C) under helium flow (5-20 Nml min ) in a micro-catalytic tubular reactor for 3 hours. The treated sample was exposed to methanol vapor (0.01-0.10 kPa) for 2 hours at 260 °C. The system was cooled at room temperature under helium for 30 minutes and then heated at the rate of 4 °C min . Effluents were continuously analyzed using a quadruple mass spectrometer (type QMG420, Balzers AG). 

Table 6.28 Mass-spectrometer types and compatible ionisation methods...

Figure 1.15 Commercial 60° magnetic sector field mass spectrometer (Type CH4, Atlas MAT) for analysis of gases. (77. Kienitz (ed.), Massenspektrometrie (1968), Verlag Chemie, Weinheim. Reproduced by permission of Wiley-VCH.)...

A magnetic sector mass spectrometer-type apparatus houses a circular trajectory of radius 25 cm which is imposed upon the ions. The accelerator voltage is raised to 5 000 V. A mass spectrum is recorded between 20-200 Da. 

Over the past two decades, QMF-based quantification assays have become the technique of choice for quantification of drug candidates and their metabolites. Combining a mass spectrometer with LC provides an additional degree of selectivity and makes the combined technique the method of choice for quantitative bioanalysis of drugs and metabolites. Among the mass spectrometer types, QMF are ideal for coupling with LC and atmospheric pressure ionization sources (ESI, APCI, APPI, DART, DESI, etc.) because QMFs have the lowest voltage requirements and vacuum requirements. 

In essence, any of the mass spectrometer types described in the GC/MS section can be used in combination with LC/MS. Double focusing mass spectrometers provide high resolution, but are very expensive. The most popular choices in LC/MS are quadrupole and ion trap mass spectrometers. TOP mass spectrometers are quickly gaining popularity in LC/MS. Recent advances in the technology make it possible to measure exact masses of the ions, which allows the unequivocal determination of their elemental composition. Thus, results comparable to those produced by high-resolution double focusing instruments can be obtained at a fraction of the cost. 

In the introductory part of this survey, it has been stated that modern mass spectrometry is no more one single spectrometric method. In several chapters some of the most important actual techniques and possible trends in modem mass spectrometry have been discussed. The complexity of the numerous ionization techniques, scan modes and different mass spectrometer types — at least at first sight — may create a feeling of obscure diffuseness. However, this complexity of performing mass spectrometry clearly demonstrates what a mass spectrometer really can be, namely a complete laboratory in itself including synthetic and analytical parts. 

Technical Aspects and Pitfalls of LC/MS Hyphenation 17 Table 1.1 Suitability and purpose of various mass spectrometer types. 

Before discussing the basic operating principles of those mass spectrometer types used in ICP-MS instrumentation, some important characteristics need to be introduced mass resolution, abundance sensitivity, mass range, and scanning speed [8]. 

The developers concluded that LipidBlast could be successfully applied to analyze MS/MS data from over 40 different mass spectrometer types and used with other available search engines and scoring algorithms, which represents a paradigm shift in lipidomics because it is not feasible to chemically synthesize all metabolites or natural products as authentic standards for library generation or quantification purposes. Moreover, the current array of MS/MS mass spectra for plant, animal, viral, and bacterial lipids in LipidBlast could be readily extended to many other important lipid classes. 

Experimental flexibility (laser wavelength/power, ionisation mode, mass spectrometer type)... 

Combination of two different mass spectrometer types in so-called hybrid instruments such as linear ion trap/orbitrap (LTQ-Orbitrap) has shown excellent detection and identification capabilities for low molecular weight compounds in various... 

All prefabricated joints were leak tested by a mass-spectrometer type leak detector before shipment. This left essentially only the field made joints to be tested after installation, thus reducing possible line failure and expensive field testing. 

Note 2—The instrument conditions and calibration matrix inverses described in this method are based on the use of a 180 magnetic-deflection type mass spectrometer (CEC Model 21-103). It is not known if the calibration matrix inverses, included in this method, are suitable for use on other mass spectrometer types. 

Wood and bone samples, chosen from each site, were radiocarbon dated using the technique of AMS in The Poznan Radiocarbon Laboratory. The laboratory is equip>p)ed with a accelerator mass spectrometer type 1,5 SDH-Pelletron, Model Compact Carbon AMS". 

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