本文件规定了使用SEC-LS测定聚合物平均分子量和分子量分布的一般方法，即尺寸排除色谱法与光散射检测相结合。根据分子量数据和随洗脱时间连续测定的重量浓度计算平均分子量和分子量分布。通过结合光散射检测器和浓度敏感检测器，绝对确定每个洗脱时间的分子量。因此，SEC-LS被归类为绝对法。 该方法适用于线性均聚物和非线性均聚物，如支化、星形、梳状、立体规则和立体- 不规则聚合物。它也适用于分子组成不能变化的异相共聚物。然而，SEC-LS不适用于分子组成可能变化的嵌段、接枝或异相共聚物。这些方法适用于从单体分子量到3000 000的分子量，但不适用于含有>；分子量为<；1 000.

This document specifies a general method for determining the average molecular weight and the molecular weight distribution of polymers using SEC-LS, i.e. size-exclusion chromatography coupled with light-scattering detection. The average molecular weight and the molecular weight distribution are calculated from molecular weight data and weight concentrations determined continuously with elution time. The molecular weight at each elution time is determined absolutely by combining a light-scattering detector with a concentration-sensitive detector. Therefore, SEC-LS is classified as an absolute method. This method is applicable to linear homopolymers and to nonlinear homopolymers such as branched, star-shaped, comb-like, stereo-regular and stereo-irregular polymers. It can also be applied to heterophasic copolymers whose molecular composition cannot vary. However, SEC-LS is not applicable to block, graft or heterophasic copolymers whose molecular composition can vary. And the methods are applicable to molecular weights ranging from that of the monomer to 3 000 000, but are not intended for samples that contain > 30 % of components having a molecular weight < 1 000.