ISSN:
0306-042X
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The hydrogen and isobutane chemical ionization mass spectra of a number of carotenoids, with symmetrical and unsymmetrical end groups, have been examined. Similar spectra were obtained with each gas. Loss of fragments, characteristic of both the polyene chain and of the end groups were shown by all compounds. Contrasting with the electron ionization spectra the chemical ionization spectra showed more abundant ions in the high mass region and a simpler fragmentation pattern. However, the diagnostic features of the [M - 92]+/[M - 106]+ ratio, established for electron ionization spectra, are retained. A unique fragmentation pattern is shown by the keto derivative, capsanthin, with consecutive losses of xylene and toluene from the [M + 1]+ ion. Attention is drawn to the significantly superior sensitivity of the chemical ionization technique over that of the electron ionization procedure. Use of the chemical ionization technique for the identification and structural examination of carotenoids thus offers advantages over the electron ionization and field desorption techniques.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bms.1200051109
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