The simplest and yet the fastest way to measure the QUALITY standard(s) of essential oils, is to measure the physical parameters such as Specific Gravity, Refractive Index, Optical Rotation (more specifically – Specific Rotation), etc.
The specific rotation helps determining the purity of the essential oil ingredients in a fast, effective, and non-destructive manner.
An instrument called Polarimeter is used for measuring the Specific Rotation. The expressive units are the Degrees (o).
The Specific Rotation of an essential oil may be explained as the optical rotation parameter obtained from the 1 g/ml oil solution in 100mm 'Polarimeter' pipe. Here the value α ('apha') suggests the purity value of the essential oil being tested.