ASTM D1218 for Refractive Index and Refractive Dispersion of Hydrocarbon Liquids
4. Summary of Test Method
4.1 The refractive index is measured using a high-resolution refractometer of an optical-mechanical or automatic digital type with the prism temperature accurately controlled. The instrument principle is based on the critical angle concept.
5. Significance and Use
5.1 Refractive index and refractive dispersion are fundamental physical properties, which can be used in conjunction with other properties to characterize pure hydrocarbons and their mixtures.
