Relative quantification of carboxylic acid metabolites by liquid chromatography - Mass spectrometry using isotopic variants of cholamine
Relative quantification of carboxylic acid metabolites by liquid chromatography - Mass spectrometry using isotopic variants of cholamine
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DOI：
10.1021/ac062416m
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发表时间：
2007-07-15
影响因子：
7.4
通讯作者：
Smith, Lloyd M.
中科院分区：
文献类型：
--
作者：
Lamos, Shane M.;Shortreed, Michael R.;Smith, Lloyd M.
Labeling reagents that differ only in their isotopic composition offer a powerful approach to achieve relative quantification between samples by ESI-MS. Heavy and light isotopic forms of cholamine, which contain a positively charged quaternary ammonium group, were synthesized and tested as new labeling reagents for the relative quantification of carboxylic acid-containing metabolites, specifically fatty acids. The positive charge on cholamine ensures that the labeled product is also positively charged under all LC-MS conditions, regardless of mobile-phase pH. This leads to high ionization efficiency and correspondingly high detection sensitivity, demonstrated here for the analysis of fatty acids in positive ion mode ESI-MS after reversed-phase separation under acidic conditions. Good accuracy and precision were obtained by mixing heavy- and light-labeled hydrolyzed egg lipid extracts in different known ratios. The relative quantification results for 10 observed fatty acids had an average absolute error of 4.6% and an average coefficient of variation (CV) of 2.6%. The labeling strategy yielded a median CV of 6% when employed for fatty acid analysis of eggs from chickens fed various dietary supplements.
