Quantification of Oligonucleotides by LC–MS/MS: The Challenges of Quantifying A Phosphorothioate Oligonucleotide and Multiple Metabolites

Abstract

We show that quantification of an oligonucleotide and multiple metabolites, including isobaric 3´ and 5´ metabolites, is achievable in a single assay through good sample clean-up and careful optimization of the LC-MS/MS parameters. The strategy presented here can be applied elsewhere and may be useful for other oligonucleotides and their metabolites.