title: Analysis of oligonucleotides by hydrophilic interaction liquid chromatography coupled to negative ion electrospray ionization mass spectrometry.
abstract: Hydrophilic interaction liquid chromatography (HILIC) is here successfully coupled to negative-ion electrospray ionization time-of-flight mass spectrometry (ESI-TOFMS) for the analysis of synthetic and chemically modified oligonucleotides. Separation was performed on a 2.1 mm × 100 mm PEEK ZIC HILIC column packed with hydrophilic stationary phase with a permanent zwitterionic functional group and a particle size of 3.5 μm with an average pore diameter of 200Å. A method was developed to separate homogeneous and heterogeneous oligonucleotides as well as methylated oligonucleotides using a quaternary pumping system containing ammonium acetate and water with an acetonitrile gradient. Analyses of oligonucleotides were performed by LC/MS with a detection limit of 2.5 picomole (20 mer) with signal to noise ratio (S/N) of 4.12. The influence of the eluent composition, type of buffer and its concentration, and organic modifier were also evaluated. The HILIC LC/MS method presented in this paper used common, 'MS friendly', mobile phases achieving sensitive and selective oligonucleotide analysis.
authors: Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom.
authors: Lingzhi
authors: L
authors: Gong
authors: James S O
authors: JS
authors: McCullagh
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D009841:Oligonucleotides / Q000032:analysis*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D009841:Oligonucleotides