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Determination of low levels of 2 H‐labeling using high‐resolution mass spectrometry: Application in studies of lipid flux and beyond
Author(s) -
Herath Kithsiri B.,
Zhong Wendy,
Yang Jiong,
Mahsut Ablatt,
Rohm Rory J.,
Shah Vinit,
CastroPerez Jose,
Zhou Haihong,
Attygalle Athula B.,
Kang Ling,
Singh Sheo,
Johns Douglas G.,
Cleary Michele A.,
Hubbard Brian K.,
Previs Stephen F.,
Roddy Thomas P.
Publication year - 2013
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.6776
Subject(s) - chemistry , mass spectrometry , isotope ratio mass spectrometry , chromatography , isotope , resolution (logic) , analytical chemistry (journal) , flux (metallurgy) , analyte , metabolic flux analysis , metabolism , biochemistry , organic chemistry , physics , quantum mechanics , artificial intelligence , computer science
RATIONALE The ability to measure low levels of 2 H‐labeling is important in studies of metabolic flux, e.g. one can estimate lipid synthesis by administering 2 H 2 O and then measuring the incorporation of 2 H into fatty acids. Unfortunately, the analyses are complicated by the presence of more abundant naturally occurring stable isotopes, e.g. 13 C. Conventional approaches rely on coupling gas chromatographic separation of lipids with either quadrupole‐mass spectrometry (q‐MS) and/or pyrolysis‐isotope ratio mass spectrometry (IRMS). The former is limited by high background labeling (primarily from 13 C) whereas the latter is not suitable for routine high‐throughput analyses. METHODS We have contrasted the use of continuous flow‐pyrolysis‐IRMS against high‐resolution mass spectrometry (i.e. Qq‐FT‐ICR MS) for measuring the 2 H‐enrichment of fatty acids and peptides. RESULTS In contrast to IRMS, which requires ~30 min per analysis, it is possible to measure the 2 H‐enrichment of palmitate via direct infusion high‐resolution mass spectrometry (HRMS) in ~3 min per sample. In addition, Qq‐FT‐ICR MS enabled measurements of the 2 H‐enrichment of peptides (which is not possible using IRMS). CONCLUSIONS High‐resolution mass spectrometry can be used to measure low levels of 2 H‐labeling so we expect that this approach will enhance studies of metabolic flux that rely on 2 H‐labeled tracers, e.g. 2 H 2 O. However, since the high‐resolution analyses require greater amounts of a given analyte one potential limitation centers on the overall sensitivity. Presumably, future advances can overcome this barrier. Copyright © 2013 John Wiley & Sons, Ltd.