Gel‐permeation chromatography. VII. Molecular weight detection of GPC effluents

Abstract

AbstractA detector system for GPC has been built consisting of a pressure cell and capillary viscometer, a constant‐flow‐rate pumping system, a concentration detector, and a computer interfacing system. This detector system provides two chromatograms; pressure drop (ΔP) versus retention volume and concentration (C) versus retention volume. Since at constant flow rate ΔP is proportional to the effluent viscosity η, the intrinsic viscosity of any effluent fraction can be computed from the equation, where subscripts 1 and 0 refer to the solution and solvent, respectively. The precision and accuracy of the above technique were evaluated using well characterized broad and narrow molecular weight distribution polymers. Both the precision and accuracy were found to be comparable to light scattering and other classical molecular weight measurement techniques. In its present form, the molecular weight detector system was found to be very sensitive to polymers with very high molecular weights, as expected, and also useful for molecular weights less than 50,000.