Characterization of polyamino acids by use of GPC-viscometry technology

The properties of polybenzyl glutamate, a well known polyamino acid vary considerably with molecular weight in both solid state and in solution. Therefore, accurate determinations of the molecular weights of these polyamino acids is essential. The dual viscometer/refractometer when used as detector system for size exclusion chromatography provides a way of determining accurate molecular weights. An indirect method of determining the molecular weight distribution (MWD) and the radius of gyration distribution (RgD) of polybenzyl glutamate is described. The MWD is calculated from the measured value of intrinsic viscosity (IV) and the known IV-to-MW relationship, at every SEC retention volume slice. Such a technique of determining MWD requires no calibration and is more precisely measurable than conventional SEC methods.