Detecting aggregates
Posted: Wed Feb 27, 2019 9:46 am
In combining SEC-MALS with other biophysical techniques, why do you see aggregates in light scattering but not in UV?
Like SAXS (small-angle X-ray scattering), light scattering intensity varies with the square of the molecular volume – in other words, it is proportional to the product of molar mass and concentration – whereas UV absorption is only proportional to the concentration. Therefore, light scattering is very sensitive to large aggregates which occur at concentrations too low to detect by UV, and even small amounts will produce a large light-scattering signal.
[answer provided by Kushol Gupta, Ph.D., University of Pennsylvania]