Diastereomer Characterization of PS-Modified Synthetic Oligonucleotides Using Cyclic IMS-MS.

Synthetic oligonucleotides have emerged as effective therapeutics that regulate gene expression to treat and prevent diseases. Oligonucleotide therapeutics are often modified with a substitution of a phosphorothioate (PS) linkage along the phosphodiester backbone to improve the drug performance and stability. The PS modification creates a mixture of diastereomer structures, increasing by a factor of 2 where is the number of PS linkages.