title: On-line biological sample cleanup for electrospray mass spectrometry using sol-gel columns.
abstract: Using a slight overpressure, a urine sample is loaded onto a monolithic photopolymerized sol-gel column that has been derivatized with hydrophobic carbon chains and then the complex urine matrix is washed with aqueous solution. A buffer containing organic solvent is used to elute the adsorbed peptides by an applied voltage and the sample is then introduced into a mass spectrometer by sheath flow electrospray. The importance of desalting this type of sample is demonstrated by an experiment that shows that the signal intensity of a test solution with neurotensin, sprayed directly into the mass spectrometer, decreased from 4.5x10(4) cps to no detectible signal when just 10% urine is added to the sample solution. We suggest that this procedure may find general application for desalting biological samples prior to mass spectrometric analysis.
authors.affiliation: Uppsala University, Department of Physical and Analytical Chemistry, Uppsala, Sweden.
authors.forename: Nina
authors.initials: N
authors.lastname: Johannesson
authors.forename: Evan
authors.initials: E
authors.lastname: Pearce
authors.forename: Maria
authors.initials: M
authors.lastname: Dulay
authors.forename: Richard N
authors.initials: RN
authors.lastname: Zare
authors.forename: Jonas
authors.initials: J
authors.lastname: Bergquist
authors.forename: Karin E
authors.initials: KE
authors.lastname: Markides
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods; D005782:Gels; D008855:Microscopy, Electron, Scanning; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014556:Urine / Q000737:chemistry*
chemical_list: D005782:Gels