targets refractive index measurement true 2020-11-12 Changed definition. [Allotrope] 2018-08-09 Moved under measurement, and changed pref label [Allotrope] RID A refractive index measurement is a measuring based on the change in refractive index of a solution. Light is passed through a hollow prism and focused on a photocell. When a liquid containing the sample is allowed to flow through the prism, the light diverges from its original path and the change in intensity and angle of the transmitted light is measured. [CHMO] RI detection refractive index measurement refractive index detection refractive index measuring measuring refractive index (quality)