Size-exclusion chromatography is routinely used in many laboratories to separate macromolecules in solution according to their size.These molecules range from synthetic polymers such as polystyrene, to natural polymers such as polysaccharides, and proteins.Historically, the primary goal of this technique has been the measurement of molecular weight.Conventionally, molecular weight was calculated by comparison of sample elution time with that of known standards.Universal calibration measures the intrinsic viscosity (Ⅳ) of polymers to overcome variation in elution time between different polymers or different polymer structures at a given molecular weight.Light scattering is now commonly used to measure the molecular weight of polymers directly, surpassing the universal calibration method; however, intrinsic viscosity still has significant value as a property in itself.