Did You Know: Solid Phase Extraction (SPE)

What is Solid Phase Extraction (SPE)?

Did you Know: SPE is the Process of Utilizing a Liquid Solvent to Extract Solid Materials

Solid Phase Extraction is an extractive process by which molecules in their solid phase are separated from each other based upon physical and chemical properties. This process is achieved by the extraction (dissolution) of certain compounds into a liquid—or solvent—and the subsequent separation from the remaining solid material, ultimately resulting in a liquid solution

Specifically, in the extraction of cannabis and hemp products, SPE is typically performed using either ethanol, hydrocarbon (butane, hexane, propane, etc.), or liquid CO2.

Here’s how SPE works:

With regards to the extraction of cannabis or hemp, the solid phase refers to the biomass or milled plant material. The next step is the addition of a solvent to the biomass, ethanol in our example, to dissolve and extract the desired molecules.

The molecules that dissolve out of the biomass and into the solvent are called solutes. These are most often a mixture of our targeted or desired compounds such as THC, CBD, or other minor cannabinoids such as CBG etc. The solutes will also include many other non-desirable compounds (e.g. chlorophyll) that may be removed using additional processes down the line. 

This new mixture of solvent (ethanol) and solutes is called a solution

A critical consideration before moving on to the next phase of the extraction and purification process, is the degree of saturation of your solution. Because solvent recovery is one of the main pinch-points in ethanol processing, it is essential that your solution be fully saturated before evaporation.