ANALYSIS AND PURIFICATION OF MONOMETHOXY-POLYETHYLENE GLYCOL BY VESICLE AND GEL-PERMEATION CHROMATOGRAPHY

Vesicle chromatography (VC) and gel permeation chromatography (GPC) we re used for characterisation and purification of monomethoxy-polyethyl ene glycol (M-PEG), a reagent for protein modification. Detection of l ow concentrations of contaminating PEG was facilitated by a very sensi tive colourimetric detection method with a detection limit of 1 mug/ml . For analytical purposes GPC on Superose 12 was superior to VC. Molec ular masses, polydispersity and percentage of contaminating PEG were e stimated. As a comparison H-1 NMR spectroscopy was carried out. The re sults were in good accordance with GPC. A two-step preparative purific ation with VC of M-PEG containing 22.9% PEG reduced the PEG content to 4.4%.