Design and performance of a low-flow capillary electrophoresis-electrospray-mass spectrometry interface using an emitter with dual beveled edge

A low‐flow electrophoresis‐mass spectrometry (CE‐MS) interface has been developed for interfacing capillary zone electrophoresis (CZE) with electrospray‐ ionization‐mass spectrometry (ESI‐MS). The interface consists of two parallel capillary columns (a separation column and a makeup column), and an emitter with a dual beveled edge. While maintaining a relatively low optimum flow rate, the dual‐beveled‐edge ESI emitter allows the use of a tip with larger orifice. Therefore, this interface is less prone to column blocking in comparison with a flat tip. Primarily attributed to low sample dilution and smaller initial droplet, the interface showed better sensitivity than a conventional sheath liquid interface. Furthermore, the interface was found to be more resistant to the presence of nonvolatile salts. By using 40 mM borate and 20 mM α‐cyclodextrin (α‐CD) as the running buffer, four major forms of gangliosides were detected by CE‐MS.