title: Electrospray ionization with a pointed carbon fiber emitter.
abstract: A new type of electrospray ionization emitter employing a pointed carbon fiber has been developed for interfacing nanoliquid sampling techniques to mass spectrometry. The pointed carbon fiber protruding from an orifice with a surrounding hydrophobic surface confines a small Taylor cone at the tip, which generates a stable electrospray at the tip point. The small Taylor cone improves the electrospray efficiency thereby enhancing the detection limit. This emitter is rugged and able to generate stable electrospray over a wide range of flow rate, ESI voltage, and surface tension variation. Using a solution of angiotensin I, the carbon fiber emitter in 75-microm-i.d. fused-silica tubing was shown to give ion current comparable to that from a commercial 8 microm orifice nanospray emitter. Use of the emitter for ESI-MS/MS analysis of peptides was examined by infusing a mixture of cytochrome c and myoglobin tryptic digest peptides. Protein identification was demonstrated at the level of less than 1 fmol of the peptide consumed. The use of the carbon fiber emitter for interfacing monolithic capillary HPLC to MS was also demonstrated.
authors.affiliation: Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA.
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.forename: Kyung Won
authors.initials: KW
authors.lastname: Ro
authors.forename: Mark
authors.initials: M
authors.lastname: Busman
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Knapp
mesh_terms: D000818:Animals; D002244:Carbon / Q000737:chemistry*; D000077482:Carbon Fiber; D045304:Cytochromes c / Q000737:chemistry; D006736:Horses; D009211:Myoglobin / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation* / Q000379:methods*
chemical_list: D000077482:Carbon Fiber; D009211:Myoglobin; D010455:Peptides; D002244:Carbon; D045304:Cytochromes c