Use of deuterium–hydrogen exchange to characterize the fragmentation pathways of arteether and its metabolites in a thermospray mass spectrometer
✍ Scribed by Hsien Tao Chi; John K. Baker
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- English
- Weight
- 479 KB
- Volume
- 28
- Category
- Article
- ISSN
- 1076-5174
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✦ Synopsis
Whereas the thermospray mass spectra of most compounds consist of only the pseudo-molecular ion with little fragmentation, the thermospray mass spectra of arteether (a cyclic endoperoxide) and its metabolites are relatively complex. Assignments of structures to individual fragments from normal spectra was particularly ambiguous because of uncertainties as to which fragments arose from ammonium ion or methanol adducts. In this study, these assignments could be resolved through the comparison of the regular spectrum with the deuteriumsxchange spectrum (in an ND40,CCH,-CD30D-D,0 mobile phase) achieved using 'sandwiched slug' injection technique. The mass spectra of arteether and four of its metabolites all showed [ M + ND4 1 + pseudo-molecular ions with greater than 91% H/D exchange, indicating a high eificiency with a minimal use of deuterated mobile phase. Most fragments showed H/D exchange rates in the 70-90% range and the isotope shift of individual spectral lines (AM) was found to be extremely useful in determining the structure of the fragment.