Disposable Emitters for On-line Capillary Zone Electrophoresis/Nanoelectrospray Mass Spectrometry

Abstract

A new method for preparing disposable microsprayers, for on-line capillary-zone electrophoresis/electrospray mass spectrometry (CZE/ES-MS) at sub-microliter per minute flow rates, is described. Different means of coupling these microsprayers to the CZE columns are presented, and compared with the more traditional one-piece capillary arrangement used for on-line CZE/ES-MS analysis. Enhancement of separation performance was obtained using capillaries coated with [(acryloylamino) propyl]trimethylammonium chloride reagents, an attractive alternative to other amine-coated capillaries. The use of disposable microsprayers provided ease of operation and flexibility for on-line CZE/ES-MS experiments, since CZE columns can be prepared independently from the microsprayers. The application of these microsprayers to unattended CZE/ES-MS operation for more than 8 hours was evaluated, and found to provide relative standard deviation values of 3-8% on peak areas and less than 1% on migration times. Full-scan mass spectral acquisition was obtained for low femtomol injections of peptides. The technique was applied to the analysis of a single chain lectin from Phaseolus vulgaris, using both CZE/ES-MS and CZE combined with tandem mass spectrometry. The mass spectral data obtained in this way provided information on the structure of glycopeptides identified in digests of the glycoprotein.

Performance of a sheathless porous tip sprayer for capillary electrophoresis–electrospray ionization-mass spectrometry of intact proteins

“…As the sprayer served as the common ground for the CE and ion source, voltages for both the separation and ESI process could be independently altered. When performing sheathless CE-ESI-MS, a significant and stable EOF is of great importance to obtain good analyte signal intensities [22,[38][39][40]. Furthermore, a typical problem in CE of proteins is that they tend to adsorb onto the fused-silica capillary wall causing band broadening and changes in EOF [41,42].…”

Structural analysis of the phase‐variable lipooligosaccharide from Haemophilus somnus strain 738

“…Oligosaccharides were viously [29]. Samples (approximately 0.1 mg/ml in 0.1 M HCOOH) were infused to the mass spectrometer at a flow rate prepared according to the following procedure.…”

Protein glycosylation analysis with capillary-based electromigrative separation techniques

“…It was applied for the characterization of the alpha subunit of recombinant human chorionic gonadotropin by CE-MS [125]. Neutral coatings may give rise to problems with spray stability of electrospray ionization mass spectrometry, sheathless interfacing is not feasible [182,[188][189][190].…”