6533b7d4fe1ef96bd12630c4

RESEARCH PRODUCT

The efficiency of gel permeation chromatography

subject

description

The resolution power of gel permeation chromatography (GPC) columns and their combinations is tested as a function of the pore sizes of the gels and as a function of the elution velocity. The efficiency of GPC is characterized by the ratio UG/UT, where UG is the experimental, and UT the theoretical, inhomogeneity. The latter quantity is obtained from absolute measurements of Mw, and Mn. The ratio passes through a minimum for a series of columns with increasing pore sizes. The minimum occurs at that column or column set which is best suited to resolving a given polymer. UG/UT for any column decreases with decreasing elution velocity. At a certain velocity UG/UT becomes 1. This velocity is usually smaller than v = 1 ml./min., but for some columns appreciably greater. Columns with low UG/UT values allow an unexpectedly good separation of mixtures of two polymers with Mw/Mn = 2 and Mw(I)/Mw(II) = 2. A compression effect toward the peaks of the two components is observed.