Time-of-Flight Mass Spectrometry

Abstract

As shown in Table I, time-of-flight mass spectrometry has had a checkered history since it became commercially available following the innovations of the Wiley-McLaren design in 1955. The Bendix/CVC instruments were used for a wide range of applications facilitated by its very fast scan capability and/or ease of access to the ion source. However, because they were seen as having both low resolution and low sensitivity, these instruments never became widely utilised in the major areas of mass spectrometry.The resurgence of interest in the time-of-flight technique since the mid '80's has been due to the advent at the forefront of mass spectrometry development of such techniques as laser and plasma desorption, laser ionisation and surface analysis, which require its ability to provide a complete spectrum for each ionisation event and also its unlimited mass range. In order for this renaissance to continue and expand, a wide base of commercially available instruments is required. As can be seen from Table II such a base now exists. This chapter is intended to provide a brief history of the time-of-flight mass spectrometer (TOFMS) over the period 1955-90 based on the progress reported at various European time-of-flight symposia. In this it is intended to act as a prelude to the exciting developments which this author anticipates for the current decade. The following chapters will provide the reader with a foretaste of the future of time-of-flight mass spectrometry.Time-of-flight mass spectrometers operate on the simple principle that a packet of ions, of differing mass/charge (m/z) ratios but equal energy or momentum, when projected into a constant electric field will separate according to their m/z ratios. Since ζ is usually unity, the separation is essentially one of mass. If the ions travel a fixed distance / to a detector, then the 'time-of-flight' (TOF) is given by 1/2 r λ l 2 m 2V ζ V J ^ J in the constant energy case (V is the accelerating voltage) and

Isobutane Made Practical as a Reagent Gas for Chemical Ionization Mass Spectrometry

“…The filament can be operated continuously to prevent the strain of power-cycling [22], but the powered filament would be exposed to gas chromatography (GC) solvent elution. Filaments can be coated with thoria or yttria so that they will produce an equal electron flux at a lower, less strenuous temperature/ionization energy [23][24][25]. Available coated filaments increase operational lifetime two to three times [26], a modest improvement upon isobutane CI results.…”

Time-of-flight mass spectrometry: State-of the-art in chemical analysis and molecular science

“…It is not the aim of this article to review the historical development of timeof-flight mass spectrometry (Cotter, 1994), but we would like to highlight its state-of-the-art, its capabilities, its usage in modem molecular science and chemical analysis, and to give an outlook on possible applications in the future.…”

Applications of Tandem Mass Spectrometry: From Structural Analysis to Fundamental Studies

“…To note that the theory underlying each mass analyser will not be addressed in this chapter so the reader is encouraged to seek this information in other sources. There are several reviews on the principle of quadrupole mass spectrometry, (Douglas 2009) ion traps, (Louris, Cooks et al 1987;Douglas, Frank et al 2005;March 2009) FTICR, (Comisarow and Marshall 1974;Marshall, Comisarow et al 1979;Marshall, Hendrickson et al 1998;Barrow, Burkitt et al 2005) time-of-flight (Price and Williams 1969;Guilhaus, Selby et al 2000) and information on sector mass spectrometry that can easily be found in mass spectrometry textbooks. (Chapman 1985;Gross 2004;Dass 2007;Hoffmann and Stroobant 2007) Common tandem mass spectrometers in space have, at least, two mass analysers.…”