The SEC-MALS-QELS system is composed of an Agilent 1260 series HPLC for size exclusion chromatography followed by a Wyatt DAWN HELEOS II multi-angle static light scattering detector, a Wyatt QELS dynamic light scattering detector, and a Wyatt T-rEx differential refractive index detector.

System components:

Wyatt DAWN HELEOS II – multi-angle (static) light scattering (MALS) detector.  The molar mass and root mean square radius of the solute are determined  by measuring the intensity of the scattered light – provided that the refractive index increment (dn/dc) of the solute/solvent system is known.

Wyatt Optilab T-rEx –  refractometer for measuring  the absolute refractive index and its increment

Wyatt QELS – quasi-elastic (dynamic) light scattering   (QELS) detector.  The diffusion coefficient/hydrodynamic radius can be determined from the temporal fluctuations in the intensity of scattered light

HPLC – with size-exclusion columns (SEC), DAD absorbance, and fluorescence detectors

In this set-up the sample components are separated according to size and characterized individually by static and dynamic light scattering, absorbance and fluorescence.

Typical applications:

  • For proteins and  nucleic acids:  measurements of  molecular weights and radii, oligomerization, heterogeneity and solubility studies, characterization of macromolecular complexes in terms of size, overall shape and composition/stoichiomentry
  • For synthetic polymers: measurements of molar mass & mass  moments,  polydispersity, conformation/branching
  • For nanoparticles: solubility and size distribution measurements and  composition /stoichiometry analysis for functionalized nanoparticles

More applications