MASS ANALYSIS AND ION DETECTION

The performance of a mass analyzer is evaluated on the basis of the following desirable features  

Fundamentals of Contemporary Mass Spectrometry, by Chhabil Dass Copyright 2007 John Wiley Sons, Inc. 

Tandem MS (MS/MS) capability, small size, and lower cost are other desirable characteristics of a mass analyzer. Miniaturization of mass spectrometers is a growing area of interest for field applications. Tandem MS is helpful in the analysis of complex mixtures. 

Before enumerating the basic principles of various types of mass analyzers, it is pertinent to outline the concept of resolution and kinetic energy as applicable to mass spectrometry. 

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The FTMS instrument operates in a very different fashion from most other types of mass spectrometers. With FTMS, the principal functions of ionisation, mass analysis and ion detection occur in the same space... 

In a mass spectrometer ion formation, mass analysis, and ion detection are combined. Various mass analysers have been developed to separate ions according to their mass-to-charge ratio. Each analyser has its own special characteristics and field of application. No mass analyser can match all possible requirements. The choice of the analyser should generally be based upon the application, the performance desired, and cost. 

For convenience, the book is organized into three parts and 15 chapters. Part I has five chapters that provide a detailed description of the instrumentation aspects of mass spectrometry. Topics in this section include modes of ionization (Chapter 2), mass analysis and ion detection (Chapter 3), tandem mass spectrometry (Chapter 4), and hyphenated separation techniques (Chapter 5). Mass... 

All mass spectrometric instruments contain regions where ionization, mass analysis, and ion detection take place. Mass spectrometry takes place at low pressure all of the mass spectrometric components are contained in a vacuum... 

In GC-MS systems, analyte ionization, mass analysis, and ion detection take place in a high-vacuum system. In most benchtop GC-MS systems, the vacuum system consists of one pumped chamber, evacuated by means of a small turbomolecular pump, backed by a mechanical fore pump. Large systems as well as modern research-grade mass spectrometers generally contain two differentially pumped vacuum chambers, separated by means of a baffle containing a slit, i.e., the ion source housing and the analyzer region. 

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