Capillary electrophoresis-fourier transform ion cyclotron resonance mass spectrometry for the identification of cationic metabolites via a pH-mediated stacking-transient isotachophoretic method.
Capillary electrophoresis-mass spectrometry (CE-MS) is still widely regarded as an emerging tool in the field of metabolomics and metabolite profiling. A major reason for this is a reported lack of sensitivity of CE-MS when compared to gas chromatography-mass spectrometry GC/MS and liquid chromatography-mass spectrometry. The problems caused by the lack of sensitivity are exacerbated when CE is coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), due to the relatively low data acquisition rate of FT-ICR MS. Here, we demonstrate the use of an online CE sample preconcentration method that uses a combination of pH-mediated stacking and transient isotachophoresis, coupled with FT-ICR MS to improve the overall detection of cationic metabolites in the bacterium Desulfovibrio vulgaris Hildenborough. This method showed a significant increase in signal-to-noise ratio when compared to CE normal sample stacking, while providing good separation efficiency, reproducibility, and linearity. Detection limits for selected amino acids were between 0.1 and 2 microM. Furthermore, FT-ICR MS detection consistently demonstrated good mass resolution and sub-ppm mass accuracy.
Baidoo
Edward E K
EE
Department of Chemical Engineering, University of California, Berkeley, California 94720, USA.
Benke
Peter I
PI
Neusüss
Christian
C
Pelzing
Matthias
M
Kruppa
Gary
G
Leary
Julie A
JA
Keasling
Jay D
JD
D000596:Amino Acids / Q000032:analysis*; D001431:Bacteriological Techniques; D002412:Cations; D017357:Cyclotrons; D016969:Desulfovibrio vulgaris / Q000737:chemistry* / Q000378:metabolism*; D019075:Electrophoresis, Capillary / Q000379:methods*; D005583:Fourier Analysis; D006863:Hydrogen-Ion Concentration; D013058:Mass Spectrometry / Q000379:methods*
D000596:Amino Acids; D002412:Cations