Electrospray ionization stability and concentration sensitivity in capillary electrophoresis-mass spectrometry using a flow-through microvial interface |
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Authors: | Lingyu Wang Yueyang Li Dazhou Chen David Da Yong Chen |
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Institution: | 1. Department of Chemistry, University of British Columbia, Vancouver, V6T 1Z1 Canada;2. Department of Analytical Chemistry and Stoichiometry, National Institution of Metrology, Beijing, P. R. China |
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Abstract: | Concentration sensitivity is a key performance indicator for analytical techniques including for capillary electrophoresis-mass spectrometry (CE–MS) with electrospray ionization (ESI). In this study, a flow-through microvial interface was used to couple CE with MS and improve the ESI stability and detection sensitivity. By infusing a peptide mixture through the interface into an MS detector at a typical flow rate for CE-MS analysis, the spatial region near the interface was mapped for MS signal intensity. When the sprayer tip was within a 6 × 6.5 × 5 mm region in front of the MS inlet, the ESI was stable with no significant loss of signal intensity for ions with m/z 239. Finite element simulations showed that the average electric field strength at the emitter tip did not change significantly with minor changes in emitter tip location. Experiments were conducted with four different mass spectrometer platforms coupled to CE via the flow-through microvial interface. Key performance indicators, that is, limit of detection (LOD) and linearity of calibration curves were measured for nine amino acids and five peptides. Inter- and intraday reproducibility were also tested. The results were shown to be suitable for quantification when internal standards were used. |
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Keywords: | Capillary electrophoresis-mass spectrometry Concentration sensitivity Electrospray ionization stability Flow-through microvial interface |
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