Sequencing of oligonucleotides using high performance liquid chromatography and electrospray mass spectrometry.

We report the sequence analysis of an oligodeoxyribonucleotide by electrospray mass spectrometry (ES-MS). For full sequence analysis of the oligomer, d(CGTAGCTACG), an enzyme digestion step followed by off-line high performance liquid chromatography was used. For ES-MS analysis, introducing the sample in an imidazole buffer with 70% acetonitrile increased the electrospray ion currents and helped reduce sodium-adduct ion peaks.