Copies of a new technical article entitled 'Determination of polymer structure by gel permeation chromatography' are available to Laboratorytalk readers
Gel Permeation Chromatography (GPC) is an established method of determining the molecular mass of polymers.
Compared to other methods of analysis, such as osmometry and static light scattering, it has the advantage that it determines not merely average values but the complete distribution of molecular weight. To meet the demand to characterise increasing complex polymers, the author describes how the use of multiple detectors overcomes the traditional limitations of conventional GPC.
The paper illustrates how light scattering detection has advantages in directly determining the molecular weight of polymers but cannot fully characterise their size.
Further the paper shows that viscosity detectors are most suitable for determining size and structure because they measure molecular differences directly and can be used over a substantially wider range of molecular weights.
However the combination of concentration, light scattering and viscosity detectors (triple detection) working simultaneously in concert with GPC is demonstrated to provide the optimum solution.
Triple detection yields the true molecular weight distributions, as well as size distributions and structural information such as degree of polymer branching in a single experiment.
For a copy of the technical article contact Viscotek Europe (see above).
