TOFMS technology

Many excellent reviews on the development, instrumentation and applications of LC-MS can be found in the literature [560-563]. Niessen [440] has recently reviewed interface technology and application of mass analysers in LC-MS. Column selection and operating conditions for LC-MS have been reviewed [564]. A guide to LC-MS has recently appeared [565]. Voress [535] has described electrospray instrumentation, Niessen [562] reviewed API, and others [566,567] have reviewed LC-PB-MS. For thermospray ionisation in MS, see refs [568,569]. Nielen and Buytenhuys [570] have discussed the potentials of LC-ESI-ToFMS and LC-MALDI-ToFMS. Miniaturisation (reduction of column i.d.) in LC-MS was recently critically evaluated [571]. LC-MS/MS was also reviewed [572]. Various books on LC-MS have appeared [164,433,434,573-575], some dealing specifically with selected ionisation modes, such as CF-FAB-MS [576] or API-MS [577],... 

Various techniques have been introduced which still lack specific applications in polymer/additive analysis, but which may reasonably be expected to lead to significant contributions in the future. Examples are LC-QToFMS, LC-multi-API-MS, GC-ToFMS, Raman spectroscopy (to a minor extent), etc. Expectations for DIP-ToFMS [132], PTV-GC-ToFMS [133] and ASE are high. The advantages of SFC [134,135], on-line multidimensional chromatographic techniques [136,137] and laser-based methods for polymer/additive analysis appear to be more distant. Table 10.33 lists some innovative polymer/additive analysis protocols. As in all endeavours, the introduction of new technology needs a champion. 

Shimma S, Furuta M, Ichimura K. Direct MS/MS analysis in mammalian tissue sections using MALDI-QIT-TOFMS and chemical inkjet technology. Surf. Interface Anal. 2006 38 1712-1714. 

Even though it appears that the technology has not been adopted yet, it is expected that TOF MS will be useful to validate the power of the GC x GC separation experiment by proving the separate identities of the vast number of resolved peaks and so show that the analyst who does not use GC X GC is missing valuable chemical compositional information on their samples. In addition, it is just as significant to TOFMS that GC X GC becomes a widespread separation tool, since this will then provide a demand for the powerful capabilities of TOFMS for identification. The GC community must wait for this to be demonstrated, and those who are working in GC X GC development are convinced that the wait will be worth it ... 

The first instrument for laser ablation/ionization was described by Sinha et al. (1984). This had most of the features of the present-day instruments unfortunately, the technology available at that time severely limited its development and utility. A major advance was made by McKeown et al. (1991) with the use of TOFMS, which enabled the recording of a complete mass spectrum for each particle. Further developments, notably by Prather s group, have culminated in the first conmiercially available ATOFMS instrument. A schematic diagram of an ATOFMS system is shown in Figure 28.33. 

The authors have a complementary cross-disciplinary expertise in material science, MS technology, ionization mechanisms, and instrumentation development. Most of the authors were partners of the EMDPA project, an acronym for Elemental and Molecular Depth Profiling Analysis by pulsed radiofrequency (RF) glow discharge time-of-flight mass spectroscopy (GD-TOFMS) within the European Union (EU) FP6 work program [5]. 

There is much more to come, such as comprehensive capillary GC, hyphenation with time-of-flight MS (capillary GC-TOFMS) and inductively coupled plasma MS (capillary GC-ICP-MS). .. to mention a few recent technological realizations. 

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