Amino acid analysis by capillary electrophoresis electrospray ionization mass spectrometry

Tomoyoshi Soga, David N. Neiger

研究成果: Article査読

399 被引用数 (Scopus)

抄録

A method for the determination of underivatized amino acids based on capillary electrophoresis coupled to electrospray ionization mass spectrometry (CE-ESI-MS) is described. To analyze free amino acids simultaneously a low acidic pH condition was used to confer positive charge on whole amino acids. The choice of the electrolyte and its concentration influenced resolution and peak shape of the amino acids, and 1 M formic acid was selected as the optimal electrolyte. Meanwhile, the sheath liquid composition had a significant effect on sensitivity and the highest sensitivity was obtained when 5 mM ammonium acetate in 50% (v/v) methanol- water was used. Protonated amino acids were roughly separated by CE and selectively detected by a quadrupole mass spectrometer with a sheath flow electrospray ionization interface. Under the optimized conditions, 19 free amino acids normally found in proteins and several physiological amino acids were well determined in less than 17 min. The detection limits for basic amino acids were between 0.3 and 1.1 μmol/L and for acidic and low molecular weight amino acids were less than 6.0 μmol/L with pressure injection of 50 mbar for 3 s (3 nL) at a signal-to-noise ratio of 3. This method is simple, rapid, and selective compared with conventional techniques and could be readily applied to the analysis of free amino acids in soy sauce.

本文言語English
ページ(範囲)1236-1241
ページ数6
ジャーナルAnalytical chemistry
72
6
DOI
出版ステータスPublished - 2000 3 15
外部発表はい

ASJC Scopus subject areas

  • Analytical Chemistry

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