Testing for residual solvents requires gas chromatography (GC). Cannalytics uses the Shimadzu GCMS-QP2020 with an HS-20 Headspace Autosampler. For this process, a small amount of extract is put into a vial and heated to mimic the natural evaporation process. The amount of solvent that is evaporated from the sample and into the air is referred to as the “headspace.” You then extract the headspace with a syringe and place the gas in the injection port of the GC. This technique is called full-evaporated technique, or FET, and utilizes the headspace autosampler for the GC.
Residual solvents are chemicals left over from the process of extracting Cannabinoids from the cannabis plant. Common solvents for such extractions include ethanol, butane, propane and hexane.
These solvents are evaporated to prepare high concentration oils and waxes. However, it is sometimes necessary to use large quantities of solvent in order to increase extraction efficiency and to achieve higher levels of purity. Since these solvents are not safe for human consumption, most states require labs to verify that all traces of the substances have been removed.
This is the easiest preparation process. Simply take an aliquot of oil/resin and put it in a headspace vial. Take the sample, heat it up and inject it into the headspace autosampler.