1.1 This test method covers the determination of molecular weight (MW) averages and the distribution of molecular weights in linear soluble polystyrene by liquid exclusion chromatography (gel permeation chromatography-GPC). The test method uses commercially available polystyrene (PS) standards and equipment for this purpose and is applicable for samples containing molecular weight components from 5000 to 3 X 10 6 g(dot)mol - 1 . This is discussed in more detail in 12.1. The test method is not absolute and requires calibration. 1.2 The values stated in SI units, based on Practice E380, are to be regarded as the standard. 1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.