Preparation and LC/MS Analysis of Oligonucleotide Therapeutics from Biological Matrices

Due to their association with other biomolecules as well as their unique chemical properties, oligonucleotide therapeutics present unique challenges in their isolation and LC/MS analysis from biological matrices. A new isolation protocol using a mixed-mode SPE cartridge is presented that demonstrates high recovery and sensitivity into the low ng/mL range. Optimization of LC/MS mobile phase conditions as well as MS analysis parameters results in improved sensitivity and identification of oligonucleotides and their metabolites.

Introduction
Therapeutic uses of oligonucleotides are becoming an increasingly popular approach to treat disease. Since the human genome was fully decoded back in 2003, researchers are gaining a rapid and comprehensive understanding of which genes code for which processes in normal human physiology. Gaining knowledge of what is normal has allowed scientists to identify abnormalities in genes which lead to disease states. Such abnormalities manifest in the incorrect coding of proteins which then leads to downstream problems with cell physiology.