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Updated: Jun 9, 2026

Ion Exchange Chromatography (IEX) Coupled to Multi-angle Light Scattering (MALS) for Protein Separation and Characterization
Published on: April 5, 2019
Simultaneous determination of polysorbate 20 and unbound polyethylene-glycol in protein solutions using new
Szabolcs Fekete1, Katalin Ganzler, Jeno Fekete
1Formulation Development, Gedeon Richter Plc, Budapest X., Gyömroi út 19-21, Hungary. fekete.szabolcs1@chello.hu
Abstract:
A novel fast and sensitive method has been developed for the specific simultaneous determination of polysorbate 20 (Tween 20) and unbound polyethylene-glycol (PEG) from liquid formulations in the presence of proteins and excipients. The quantitative determination is based on a fast liquid chromatographic (HPLC) separation and condensation nucleation light scattering detection (CNLSD or NQAD™). The method uses a Kinetex core-shell column (100 mm × 3 mm, 2.6 μm) and methanol-water-trifluoroacetic acid mobile phase. The rapid HPLC-CNLSD method presented here is suitable for quantifying polysorbate 20 in the range of 10-60 μg/ml and unbound PEG in the range of 2-40 μg/ml in protein solutions within good manufacturing practices (GMP) of the pharmaceutical industry.
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