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Mass spectrometric analysis of cardiac glycosides by the desorption/ionization technique potassium ion ionization of desorbed species
Author(s) -
Light Karen J.,
Kassel Daniel B.,
Allison John
Publication year - 1989
Publication title -
biomedical and environmental mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0887-6134
DOI - 10.1002/bms.1200180306
Subject(s) - ionization , chemistry , desorption , ion , potassium , mass spectrometry , ambient ionization , glycoside , analytical chemistry (journal) , chromatography , chemical ionization , organic chemistry , adsorption
The analysis of cardiac glycosides by the desorption/ionization (D/I) mass spectrometric technique potassium ion ionization of desorbed species (K + IDS) is presented. K + IDS mass spectra of digitonin, digoxin, digoxigenin, digitoxin and ouabain are discussed to demonstrate the capabilities of this D/I method. The K + IDS analysis consists of two steps: thermal desorption of neutral molecules representative of the analyte, followed by gas‐phase addition of K + ions to these species. Structural and molecular weight information of the cardiac glycosides is obtained with the K + IDS technique. The most intense peak in the K + IDS mass spectrum of an analyte, M, is frequently the [M]K + ion. Interpretation of the K + IDS mass spectra is simple, since one thermal degradation mechanism dominates. This mechanism is a 1,2‐elimination process. A variation of the original K + IDS technique, performed by changing the ionizing metal from K + to Na + (i.e. Na + IDS), is presented for the analysis of digoxin. The Na + IDS mass spectrum of digoxin contains more structural information than the K + IDS mass spectrum of that compound. This may lead to a means of controlling the types of information obtainable with this D/I technique by varying the cation that is thermionically generated. K + IDS analyses can be performed rapidly, no sample derivatization is necessary, no matrix is required and little instrument modification is necessary.