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Electrospray ionization mass spectrometry of ginsenosides
Author(s) -
Miao XiuSheng,
Metcalfe Chris D.,
Hao Chunyan,
March Raymond E.
Publication year - 2002
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.309
Subject(s) - chemistry , ion , analytical chemistry (journal) , mass spectrometry , electrospray ionization , fragmentation (computing) , collision induced dissociation , mass spectrum , dissociation (chemistry) , ionization , tandem mass spectrometry , chromatography , organic chemistry , computer science , operating system
Ginsenosides R b1 , R b2 , R c , R d , R e , R f , R g1 , R g2 and F 11 were studied systematically by electrospray ionization mass spectrometry in positive‐ and negative‐ion modes with a mobile‐phase additive, ammonium acetate. In general, ion sensitivities for the ginsenosides were greater in the negative‐ion mode, but more structural information on the ginsenosides was obtained in the positive‐ion mode. [M + H] + , [M + NH 4 ] + , [M + Na] + and [M + K] + ions were observed for all of the ginsenosides studied, with the exception of R f and F 11 , for which [M + NH 4 ] + ions were not observed. The signal intensities of [M + H] + , [M + NH 4 ] + , [M + Na] + and [M + K] + ions varied with the cone voltage. The highest signal intensities for [M + H] + and [M + NH 4 ] + ions were obtained at low cone voltage (15–30 V), whereas those for [M + Na] + and [M + K] + ions were obtained at relatively high cone voltage (70–90 V). Collision‐induced dissociation yielded characteristic positively charged fragment ions at m / z 407, 425 and 443 for (20 S )‐protopanaxadiol, m / z 405, 423 and 441 for (20 S )‐protopanaxatriol and m / z 421, 439, 457 and 475 for (24 R )‐pseudoginsenoside F 11 . Ginsenoside types were identified by these characteristic ions and the charged saccharide groups. Glycosidic bond cleavage and elimination of H 2 O were the two major fragmentation pathways observed in the product ion mass spectra of [M + H] + and [M + NH 4 ] + . In the product ion mass spectra of [M − H] − , the major fragmentation route observed was glycosidic bond cleavage. Adduct ions [M + 2AcO + Na] − , [M + AcO] − , [M − CH 2 O + AcO] − , [M + 2AcO] 2− , [M − H + AcO] 2− and [M − 2H] 2− were observed at low cone voltage (15–30 V) only. Copyright © 2002 John Wiley & Sons, Ltd.