7. Draw GPC chromatograms of a mixture of PS (MW = 5,000), PS (MW = 10,000) and PMMA (MW = 5,000). RI is used as the instrument detector, THF is the mobile phase and toluene is used as the marker. While dissolving the polymer mixture in THF, PMMA has smaller size than PS of the identical MW. Advices: - refractive index (RI) of PS = 1.0 Rl of Toluene = 0.9 - Rl of THF = 0.8 RI of PMMA = 1.4