Capillary electrophoresis-mass spectrometry using a flow-through microvial interface for cationic metabolome analysis

The application of CE-MS in the field of metabolomics is underrepresented, even though it is in principle highly suited for the analysis of small charged compounds, as many metabolites are. Moreover, a robust coupling, using the sheath-liquid (SL) assisted interface was already presented more than a decade ago. A lack of concentration sensitivity is often mentioned as a reason for the underrepresentation of CE-MS in metabolomics. This is caused by postcolumn dilution of the sample with SL, which is typically delivered at a flow rate of 1-10 μL/min. In this study, we investigated the performance of the flow-through microvial (MV) assisted CE-MS interface for cationic metabolomics. With this interface, only a little liquid is added post-column, i.e. typically 100-500 nL/min. For the evaluation, we used a metabolite mix comprising of 45 important cationic metabolites and compared the sensitivity and LOD of both devices. The performance of the CE-MS system was significantly improved by using the MV-assisted interface; the sensitivity was increased more than three times and the LOD decreased more than five times. Then, we analyzed single zebrafish embryos, to demonstrate the method on a volume-limited biological sample. In comparison with SLassisted CE-MS, twice as many molecular features were found, of which several could be identified. These results demonstrate the good potential of the MV interface for enhancing the coverage of the metabolome.

P.W. Lindenburg, R. Ramautar, R.G. Jayo, D.D.Y. Chen, T. Hankemeier
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Epub ahead of print
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Date of publication: 
October, 2013
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