Calibration of gel-permeation columns would be most directly performed by using narrow fractions of the polymer under study. However, obtaining fractions sufficiently narrow for this purpose is laborious and not always feasible. Further, for columns with a wide distribution of pore sizes, e.g., lo3-lo7 A, a simple, two-parameter, semilog relation will not always adequately represent the dependence of molecular weight on elution volume. This note describes a novel approach for calibrating gel-permeation columns by use of polymers whose molecular weight distributions may be approximated by a generalized, two-parameter, single-peak distribution function similar to that suggested by Schulzl and Zimm.z This distribution function should be valid for most linear polymers having a single-peaked molecular weight distribution.According to this function, the weight fraction dw of a species having a molecular weight between M and M + dM is: dw = p' + qr(z + 1)]-lMZe-~WM
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