Mass spectra can be quite complex and difficult to interpret. To help in compound identification, after a spectrum of a compound is obtained on a computer interfaced to a GC MS instrument, the chemist can often search a large database of mass spectral data for matches. Using this technique, even beginning students can determine the identity of a compound in a few minutes.
Another web site that provides an introduction to mass spectrometry is provided by the American Association for Mass Spectrometry (ASMS):
Thanks to Professor Veronica Bierbaum for reading and editing the chapter and to the National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan, for the mass spectra (http://www.aist.go.jp/RIODB/SDBS/menu-e.html).