252Californium plasma desorption mass spectrometry.

The mass spectrometry of involatile molecules presents problems not encountered when the molecule can be volatilized and subsequently ionized in the gas phase. The production of ions from a condensed phase is sensitively dependent on the properties of the matrix. The presence of impurities in the sample can totally quench molecular ion formation even though the sample contains a high percentage of the molecule of interest. One of the methods used for the mass spectrometry of involatile molecules is 252Californium plasma desorption mass spectrometry. The basic principles of this method will be presented with examples of its application that include the identification of involatile marine toxins (including the red tide toxins). We shall also introduce a new variation in mass spectrometry, a study of time-dependent effects, a technique that can be used to follow dynamic changes as a result of chemical reactions occurring in the sample at room temperature. This is possible in 252Californium plasma desorption mass spectrometry because the sample is conserved during the analysis.