title: Sheathless capillary electrophoresis/electrospray mass spectrometry using a carbon-coated tapered fused-silica capillary with a beveled edge.
abstract: A tapered capillary tip containing a beveled edge was developed for use in sheathless capillary electrophoresis/electrospray mass spectrometry (CE/ESI-MS). The optimal flow rate of a 75-microm-i.d., 90-microm-o.d. beveled tapered capillary tip was similar to a conventional flat tapered tip with a 25-microm orifice. Using a mixture of coptisine, berberine, and palmatine chloride, the sheathless CE/ ESI-MS sensitivity of a beveled 75 microm tapered tip capillary was found to be similar to a 25 microm flat tip. Although both tips offer similar CE/ESI-MS sensitivity, the beveled tapered capillary tip is more rugged and durable than a conventional 25-microm tapered capillary because of the larger outside diameter and inside diameter. To make electrical contact, the capillary tip was smeared with paint marker followed by the application of a carbon coating using a graphite pencil. Using this refined carbon-coating procedure, the capillary tip can be operated with aprotic solvents.
authors.affiliation: Department of Chemistry, National Taiwan University, Taipei, ROC.
authors.forename: Y Z
authors.initials: YZ
authors.lastname: Chang
authors.forename: Y R
authors.initials: YR
authors.lastname: Chen
authors.forename: G R
authors.initials: GR
authors.lastname: Her
mesh_terms: D002244:Carbon; D019075:Electrophoresis, Capillary / Q000295:instrumentation* / Q000379:methods*; D012822:Silicon Dioxide; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation* / Q000379:methods*
chemical_list: D002244:Carbon; D012822:Silicon Dioxide