The refractive index increment dn/dc is the dependency of the refractive index to the concentration. The measuring value is needed in many areas, e.g. for the evaluation of light scattering measurements, for the determination of the sedimentation in ultracentrifuges, and for the determination of diffusion.
For these applications the preciseness of an Abbe-
Schematic illustration of a Differential refractometer according to Bodmann