On the formation of doubly charged fragment and cluster ions of oxygen‐ and sulfur‐containing substances in field ionization and field desorption mass spectrometry

The appearance of doubly charged molecular, fragment and cluster ions in the field desorption and field ionization mass spectra of thiotepa are discussed. A comparison with the field-desorption mass spectra of some other oxygen- and sulfur-containing compounds is made and the conclusion reached, that the formation of doubly charged fragment [MO]2+, [MS]2+, and cluster [(MO)M]2+, [(MS)M]2+ ions is a characteristic behaviour of several types of substances containing O and S groups under the conditions of high electric field.