title: Use of cation exchange chromatography for human C-peptide isotope dilution - mass spectrometric assay.
abstract: An application of ion exchange chromatography for C-peptide analysis is described here. At the stage of C-peptide isolation, a strong cation exchanger (SP HP or MonoS) was used to purify the analyte from ballast proteins and peptides. The conditions of ion-exchange chromatographic separations were optimized using theoretical modeling of the net surface electric charge of the peptide as a function of pH. The purified and concentrated sample was further subjected to LC-MS/MS. In order to improve the reliability of analysis, two fragment ions were monitored simultaneously both for native C-peptide and internal standard, isotopically labeled C-peptides analogues (fragments with m/z of 927.7 and 147.2). Using ion-exchange chromatography, it became possible to process larger sample volumes, important for testing patients with very low C peptide levels, compared to currently used solid phase extraction methods.
authors.affiliation: University of Missouri, School of Medicine, One Hospital Drive, Columbia, MO 65212, USA. stoyanova@health.missouri.edu
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Stoyanov
authors.forename: Curt L
authors.initials: CL
authors.lastname: Rohlfing
authors.forename: Shawn
authors.initials: S
authors.lastname: Connolly
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Roberts
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Nauser
authors.forename: Randie R
authors.initials: RR
authors.lastname: Little
mesh_terms: D002096:C-Peptide / Q000097:blood / Q000737:chemistry*; D002412:Cations; D002852:Chromatography, Ion Exchange / Q000379:methods*; D004560:Electricity; D006801:Humans; D006863:Hydrogen-Ion Concentration; D016014:Linear Models; D000432:Methanol; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D002096:C-Peptide; D002412:Cations; D000432:Methanol
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