Size Exclusion chromatography with multi-angled light scattering


Size exclusion (SEC) alone will separate molecules based on hydrodynamic volume to give a mass estimate but has limitations.  Assumptions are that the sample will have the same molecular conformation as the calibration standard so cannot measure if the sample is elongated, branching, inherently disordered or has electrostatic or hydrophobic interactions. 

Multi-Angle Light Scattering (MALS) is used to accurately measure the intensity of scattered light.  Light scattering intensity is proportional to weight-averaged molar mass in solution.  Combining SEC, MALS and concentration detectors in a SEC-MALS experiment allows for more accurate mass measurements than SEC or MALS alone. By using two concentration detectors (RI and UV) the molar mass and weight-fraction of a modifier can be determined.  


SEC-MALS system with light scattering detectors and refractive index (RI) detectors from Wyatt technology and liquid chromatography system with UV detector from Agilent.  Plus the DynoPro NanoStar dynamic light scattering (DLS) detector which can be used in conjunction with MALS or as stand-alone using 1uL quartz cuvette.


Wyatt DAWN Multi-angle light scattering includes 18-angles of scattering detection for the broadest and most accurate measurements of molar mass (Mw) and root mean square radius (Rg). 

Wyatt Optilab Differential refractive index(RI) detector. Measures differential and absolute refractive index (dRI and aRI) with high sensitivity and dynamic range.  Light source matched to MALS laser. Temperature control 4 - 65C.

DynaPro NanoStar Dynamic light scattering (DLS) detector.  For determination of nanoparticle size from 0.2 – 2500nm Rh.  Incorporates dedicated static light scattering detector for direct determination of molar mass of proteins and other macromolecules.  Temperature range -15 to 150C. 


  • Agilent 1260 Infinity II Liquid Chromatography System
  • Agilent 1260 Infinity II Analytical fraction collector
  • Agilent 1260 Infinity II variable wavelength detector
  • Agilent 1260 Infinity II vial sampler


  • SEC Analytical Column, 5µM 500Å 7.8 x 300mm 
  • SEC Guard Column, 5µM 500Å 7.8mm ID 
  • SEC Analytical Column, 5µM 300Å 7.8mm ID
  • SEC Guard Column, 5µM 300Å 7.8mm ID
  • SEC Analytical Column, 5µM 100Å 7.8mm ID
  • SEC Guard Column, 5µM 100Å 7.8mm ID


Absolute molar mass and size measurements

Light scattering for size & size distributions

Multi-angle light scattering with field-flow fractionation