Use of Capillary Electrophoresis for Concentration Analysis of Phosphorothioate Oligonucleotides

The rapid advance of phosphorothioate oligonucleotides in clinical development has accelerated the need for accurate quantitation of these compounds for quality control and bioanalytical applications (1 ). Whereas slab-gel polyacrylamide gel electrophoresis has been in routine use for the analysis of oligonucleotides, it has been replaced by capillary gel electrophoresis (CGE) as the technique of choice for length-based separation of synthetic oligonucleotides (2 –10 ). This can be attributed to many factors including, superior resolution as a result of 10–100-fold higher electric fields, on line detection, and automation.