BASICS OF MASS SPECTROMETRY

In DENDRAL s termininology these three steps were simply called plan, generate and test. In the best case, the structure with a virtual spectrum most similar to the experimental spectrum is the correct solution. Instead, one is often left with either a huge or an empty structure space after structure generation or verification. In these cases, parameters of interpretation or selection have to be modified. Further, it should be possible to use prior knowledge (e.g. the synthesis or source of the analyte) in this process. 

For structure verification, a database of known spectrum-structure pairs is indispensable. Statistical models for NMR peak prediction are trained on available data [151,196,197,198]. In Section 8.4 we will see how database spectra are used to select structure candidates via MS. 

The name mass spectrometry already shows that it is different from other spectroscopic methods. In contrast to NMR and IR spectroscopy, MS observes ions, i.e. charged particles derived from the analyte, rather than the molecules of the analyte themselves. The occurrence and types of the various ions observed depend on type and energy of ionization. The recent interest in MS is due to 

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Glish, G.L. Vachet, R.W. The Basics of Mass Spectrometry in riie Twenty-First C tury. Nat. Rev. Drug Discovery 2003, 2, 140-150. 

For those readers who are not yet familiar with mass spectrometry, the introduction provides an explanation of the basics of mass spectrometry and its instrumentation as well as practical aspects and applications in bioanalysis. Next, a block of three chapters shows different affinity selection procedures suitable to identify hits from combinatorial compound libraries. This subject, being metaphorically speaking a search for a needle in a haystack, is of outstanding relevance for big pharma . The techniques described here offer real high throughput capabilities and are implemented already in the routine industrial screening... 

G. L. Glish and R. W. Vachet,The basics of mass spectrometry in the twenty-first century. Nature Rev. Drug Discovery 2 (2003), 140-150. 

Barnes, S., Basics of mass spectrometry. Retrieved 2006, from http //www.uab.edu/botanicals/ workshop/pdf/2006 d 1 /6BamesBotanicalsLC-MS.pdf... 

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