Test No. 118
Subtitle: Determination of the Number-Average Molecular Weight and the Molecular Weight Distribution of Polymers using Gel Permeation Chromatography
By: Organisation for Economic Co-operation and Development
Series: OECD Guidelines for the Testing of Chemicals, Section 1
Publisher: OECD Publishing
Published: 1996
Place of publication: Paris
Language: eng
Format: [electronic resource] /
ISBN-13: 9789264069848
Subjects: Ecology; Euthenics; Nature and nurture; Adaptation (Biology)
Description: This Test guideline describes the Gel Permeation Chromatography (GPC). This method permits to determine the molecular weight distribution and the average molecular weights (Mn, Mw). GPC is a special type of liquid chromatography in which the sample is separated according to the hydrodynamic volumes of the individual constituents.According to their size, the eluted molecules can or not penetrate in the porous material (typically an organic gel) of which the columns are filled. Thus, the smallest molecules are retained whereas largest elute more quickly. At exit of column, detectors (generally by differential refractometry) provide the refractive index or UV-absorption and yield a simple distribution curve. However, to attribute actual molecular weight values to the curve, it is necessary to calibrate the column by passing down polymers of known molecular weight and, ideally, of broadly similar structure, e.g. various polystyrene standards. For each sample analyzed, two independent experiments must be undertaken. They have to be analysed individually. Mn, Mw, Mw/Mn must be provided for every measurement.