1.1 Objective. This standard gives the method for determining the rotational power of essential oils. 1.2 Definition. The "rotary power" is the angle a by which the plane of polarization of light rotates, when a layer of essential oil is examined, under specific conditions. o The radiation to be used has a wavelength of 5893 + 3 A corresponding to line D of sodium radiation, of the Frauenhofer spectrum. Carry out the determination generally at a temperature of approximately 20°C and express it in degrees of a circle corresponding to the thickness of 10cm of the product when the latter is liquid. Special cases are regulated in product standards which specify the use of temperatures above 20°C or special techniques.
NBN 444-1956 history
1956NBN 444-1956 Optical rotation ability of essential oils