[OLIGNUCLEOTIDES] Absolute quantification and P=O/P=S ratio in a single ICP-MS/MS run

17th February 2020

Access now this new article published in Elsevier Journal of Pharmaceutical and Biomedical Analysis

Authors: Juliusz Bianga, Magali Perez, Damien Mouvet, Caroline Cajot, Philippe De Raeve, Arnaud Delobel

JBPA Oligonucleotides
Full article: https://www.sciencedirect.com/science/article/abs/pii/S0731708519330407?


  • Absolute quantification of oligonucleotides based on phosphorus content

  • Determination of phosphodiester to phosphorothioate ratio

  • Readily applicable in a GMP environment for characterization and batch release


A new analytical method based on ICP-MS/MS is proposed for the characterization of synthetic phosphorothioate oligonucleotides. Absolute quantification of oligonucleotides is challenging, as well as the determination of phosphodiester to phosphorothioate ratio for phosphorothioate oligonucleotides. Both are considered as critical quality attributes and should be determined using robust validated methods.

The method we developed was designed to be easy to apply, fast, and robust. It allows simultaneous absolute quantification of an oligonucleotide (based on the quantification of phosphorus), determination of the phosphodiester to phosphorothioate ratio (based on the quantification of phosphorus and sulfur) and optionally determination of sodium (or any other metal) as a counter ion. The performance of the method was demonstrated on O,O-diethyl thiophosphate potassium salt, a well characterized model substance that possesses similar composition to phosphorothioate oligonucleotides. Method was also tested on different synthetic phophorothioate oligonucleotides, showing excellent accuracy and precision.

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