In a typical light scattering experiment, a well collimated, single frequency, polarized light beam (i.e., from a laser) is used to illuminate a solution containing a suspension of the macromolecules or nanoparticles of interest. The electric field of the polarized light beam is preferably produced perpendicular to the plane in which the intensity and angular dependence of the subsequently scattered light is to be measured.
The overall intensity carries information about the molar mass, while the angular dependence within the horizontal plane carries information about the size of the macromolecule.
Coupling MALS with an in-line concentration detector following a sample separation technique such as AF4 or SEC permits to determine the molar mass of the eluting sample in addition to its root-mean-square radius.
AF4-MALS is applicable to a wide range of analytes including proteins, polymers, viruses, gene vectors, liposomal drug nanoparticles, engineered nanoparticles, colloids and nanoemulsions.