Chromatography

Chromatography is a family of laboratory techniques that separate the components of a mixture by moving them at different speeds through a stationary material.

A sample is carried by a liquid or gas, called the mobile phase, through a column packed with a stationary phase. Compounds interact with the stationary phase to different degrees, so they emerge at different times and can be detected and measured one by one. The time a compound takes to emerge, and the size of its signal, are compared with known reference standards.

Nearly every cannabinoid figure on a certificate of analysis comes from some form of chromatography, most often liquid chromatography for potency and gas or liquid chromatography for pesticides, solvents and terpenes. The same principle, run at larger scale, is used in processing to separate and remove specific compounds, including THC, from an extract. A chromatographic result is only as good as the method and the reference standards behind it, which is one reason laboratory accreditation matters.