No abstract

No abstract

No abstract

When a thermally labile analyte Is placed on a potassium thermionic emitter and heated, Ions representative of the sample are formed. This has been developed Into a new Ionization technique which utilizes a thermionic emitter probe that can be used with any mass spectrometer having a direct Insertion probe. A possible mechanism for this Ionization method is discussed. The proposed mechanism Involves the gas-phase addition of emitted potassium Ions to neutrals desorbed from the surface. This Ionization method Is referred to as K+IDS (K+ Ionization of desorbed species). Examples of K+IDS spectra are given for a variety of compounds Including saccharides, pharmaceuticals, peptides, steroids, and polymers. The analysis of mixtures Is also demonstrated here.In addition to the K+ Ionization of desorbed species, surface Ionization can occur. Surface Ionization Is demonstrated for the class of compounds that Includes xanthine and theophylline. Surface Ionization can also occur for thermally labile compounds, producing negative Ions; this Is shown here by use of a peptide as an example.

No abstract