title: Large-volume sample on-line concentration of angiotensins in non-aqueous capillary electrophoresis.
abstract: A single step on-line concentration and separation method for peptides in non-aqueous capillary electrophoresis was developed. ACN containing 50 mM tetraethylammonium perchlorate was used as the electrophoretic medium; angiotensins I-IV were separated as a result of the differences in the magnitudes of their interactions with perchlorate anions. When the sample solution (ACN containing 0.5% trifluoroacetic acid and angiotensins) was injected as a large-volume plug, the analytes were concentrated at the inlet end of the capillary by both sweeping and stacking mechanisms; the separation procedure then started automatically without any operations such as polarity change. It was found that the concentration of analytes, injection period, and concentration of tetraethylammonium perchlorate in the electrophoretic medium were important factors for both separation and concentration efficiencies. The angiotensins were concentrated and separated with the large-volume injection of up to 80% of the effective capillary length.
authors.affiliation: Department of Materials Science and Engineering, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan. kitagawa.shinya@nitech.ac.jp
authors.forename: Shinya
authors.initials: S
authors.lastname: Kitagawa
authors.forename: Akitsugu
authors.initials: A
authors.lastname: Noji
authors.forename: Naofumi
authors.initials: N
authors.lastname: Matsushita
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakagawa
authors.forename: Takahiro
authors.initials: T
authors.lastname: Asai
authors.forename: Hajime
authors.initials: H
authors.lastname: Ohitani
mesh_terms: D000097:Acetonitriles; D000809:Angiotensins / Q000737:chemistry / Q000302:isolation & purification*; D000838:Anions / Q000737:chemistry; D004553:Electric Conductivity; D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D010472:Perchlorates / Q000737:chemistry; D014269:Trifluoroacetic Acid / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D000809:Angiotensins; D000838:Anions; D010472:Perchlorates; D014269:Trifluoroacetic Acid; C494474:perchlorate; C032159:acetonitrile