Comprehensive hydrophilic interaction and ion-pair reversed-phase liquid chromatography for analysis of di- to deca-oligonucleotides

• Published in: Journal of Chromatography A Vol. 1255; pp. 237 - 243
• Main Authors: Li, Qin, Lynen, Frédéric, Wang, Jian, Li, Hanlin, Xu, Guowang, Sandra, Pat
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 14.09.2012
• Subjects: acetates; Buffers; Chromatography; Chromatography, High Pressure Liquid - instrumentation; Chromatography, High Pressure Liquid - methods; Chromatography, Reverse-Phase - instrumentation; Chromatography, Reverse-Phase - methods; Comprehensive two-dimensional liquid chromatography; electrospray ionization mass spectrometry; Ethylamines - chemistry; high performance liquid chromatography; hydrophilic interaction chromatography; Hydrophilic interaction liquid chromatography; hydrophilicity; Hydrophobic and Hydrophilic Interactions; Ion-pair reversed-phase liquid chromatography; Ionization; LC × LC interface; Liquid chromatography; Oligonucleotides; Oligonucleotides - analysis; Oligonucleotides - chemistry; Reproducibility of Results; reversed-phase liquid chromatography; silica; triethylamine; Two dimensional; Valves; Hydrophilic interaction liquid chromatography; LC×LC interface; Comprehensive two-dimensional liquid chromatography; Ion-pair reversed-phase liquid chromatography; Oligonucleotides
• ISSN: 0021-9673; 1873-3778
• DOI: 10.1016/j.chroma.2011.11.062

► Comprehensive LC×LC for analysis of di- to deca-oligonucleotides is described. ► HILIC is used in the first dimension and IP-RPLC in the second dimension. ► The coupling of HILIC×IP-RPLC to ESI-MS is presented. A comprehensive two-dimensional HPLC approach with a high degree of orthogonality was developed for analysis of di- to deca-oligonucleotides (ONs). Hydrophilic interaction liquid chromatography (HILIC) was used in the first dimension, and ion-pair reversed-phase liquid chromatography (IP-RPLC) was employed in the second dimension. The two dimensions were connected via a ten-port valve interface equipped with octadecyl silica (ODS) traps to immobilize and focus the ONs eluting from the first dimension prior to IP-RPLC separation. An aqueous make-up flow was used for effective trapping. The comprehensive two-dimensional HPLC system was optimized with a mixture consisting of 27 oligonucleotide standards. An overall chromatographic peak capacity of 500 was obtained. The use of the volatile buffer triethylamine acetate in the second dimension allowed straightforward coupling to electrospray ionization mass spectrometry (ESI-MS) and detection of each ON in the negative ionization mode.