Applications of Other Related Techniques

Among the other soft ionization techniques is laser microprobe mass spectrometry (LAMMA) in which a laser pulse is used to vaporize a small amount of sample, as discussed in a 1982 review (108). Of interest to us is the application to the study of some cobalamins (109). (M + H) and (M - H) ions were observed in the positive and negative ion modes, respectively. However, there were few other high-mass fragments that could be used to impart structural information. 

Schulten (110, 111) has used laser-assisted field desorption mass spectrometry to study some inorganic and organometallic systems. This method is intermediate between LAMMA and simple FD. Metal cations predominate from inorganic salts. The technique also showed clusters of the type reported from both FAB and SIMS studies. By carefully controlling the laser, a chlorophyll molecular ion could be obtained as well as fragments relating to its structure. 

The rarest of these specialized techniques, californium-252 plasma desorption mass spectrometry, has not been applied extensively to inorganic systems, though in a 1983 review (115) Macfarlane quotes several examples, such as polymeric platinum blue, with molecular ions extending to m/z 3000. At present there are only 10 functioning systems and this certainly limits its growth. 

In conclusion, I hope that I have shown that fast-atom bombardment mass spectrometry is a potentially useful tool for the synthetic chemist working in many areas of inorganic, organometallic, and coordination chemistry. In addition, as further fundamental research is done in the field with these applications in mind, the technique should become as routine as IR or NMR. Combined with developments in high-resolution NMR of solids, FAB should provide particularly useful data on supported catalytic reactions. Certainly FAB and the other complementary mass spectrometric techniques, mentioned in less detail, constitute a major way of quickly characterizing new compounds. 

In the 5 months since this article was written, literature relevant to it has increased by one-third. At the end of the original 117 references I have added important new references, along with key words for each that will relate them to the text. They are presented topically in approximately the same order as material is discussed in the text, and I hope they will be of value. 

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