title: Enhanced mass detection of oligonucleotides using reverse-phase high-performance liquid chromatography/electrospray ionization ion-trap mass spectrometry.
abstract: A new method providing enhanced sensitivity for the analysis of oligonucleotides using an on-line coupled system of reversed-phase high-performance liquid chromatography (RP-HPLC) and electrospray ionization ion-trap mass spectrometry (ESI-MS) has been developed. The presented method allows the use of the standard gradient elution of 0.1 M triethylammonium acetate (TEAA) buffer (adjusted to pH 7.0 with acetic acid) and acetonitrile that is typically used for the separation of oligonucleotides in RP-HPLC. An added feature of this method is the ability to combine and mix additional 0.1 M imidazole in acetonitrile after the separation column for improved ESI-MS performance. This is similar to the post-column reaction method in liquid chromatography (LC) and the liquid sheath flow method in LC/ESI-MS, both of which offer the advantage of not compromising the chromatographic separation conditions. The application of this new method is demonstrated to afford improved sensitivity for the analysis of oligonucleotides (20-50 mer) via on-line coupled HPLC/ESI-MS analysis and purification systems.
authors.affiliation: Naka Customer Center, Hitachi Science Systems Co., 882 Ichige, Hitachinaka 312-8504, Japan.
authors.forename: Kisaburo
authors.initials: K
authors.lastname: Deguchi
authors.forename: Masako
authors.initials: M
authors.lastname: Ishikawa
authors.forename: Takefumi
authors.initials: T
authors.lastname: Yokokura
authors.forename: Izumi
authors.initials: I
authors.lastname: Ogata
authors.forename: Shinya
authors.initials: S
authors.lastname: Ito
authors.forename: Tadao
authors.initials: T
authors.lastname: Mimura
authors.forename: Chad
authors.initials: C
authors.lastname: Ostrander
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D008970:Molecular Weight; D009841:Oligonucleotides / Q000032:analysis* / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods*
chemical_list: D009841:Oligonucleotides