Molecular Weight and Polydispersity of Calf-Thymus DNA: Static Light-Scattering and Size-Exclusion Chromatography with Dual Detection

摘要

Plausible calf-thymus DNA molecular weight distribution can be obtained by size-exclusion chromatography with dual low-angle light scattering/refractometric detection at sufficiently low flow rate. The distribution extends over three decades of molecular weight and is characterized by weight average molecular weight M_w = 8418000 and polydispersity index M_w/ M_n = 5.2. After strongly scattering impurities had been removed from the sample using adsorption properties of the 3 μm mixed-cellulose-ester filter membranes, static light-scattering measurement in flow injection mode was feasible and gave M_w = 8580000, corroborating the veracity of SEC results.