Greening Peptide Purification Through Replacement of Acetonitrile with Ethanol

Introduction

Increased global demand for peptide therapeutics has put a renewed emphasis on improving the efficiency and sustainability of peptide production, and have included efforts to identify greener alternatives to acetonitrile for HPLC purification. Ethanol has been identified as an ideal alternative, based on both a low UV-cutoff and similar separation characteristics, but its higher viscosity has hindered routine use due to higher system back pressures. This work describes the use of an optimized approach (using a novel integrated heating system) for elevated temperature HPLC purification that enables routine access to ethanol even with 5 µm particle size columns. Additionally, an assessment of the potential for esterification side-reactions known to occur with methanol were undertaken with ethanol to establish the robustness of the approach.