Residual Solvent Testing

Residual Solvent Overview

Highly concentrated oils and purified extracts are created through the use of hydrocarbon gases and organic solvents. If proper quality measurements are not taken, then the finished product may contain residue from the gases or solvents that the consumer could ingest or inhale.

Testing Technologies Inc. can test for residual solvents in extracts or edibles. To detect residual solvents, we use headspace-GC with both FID and mass spectrometer detectors. In addition to our standard residual solvent panel, we can test for any number of residual solvents.

WA I-502 Limits

Processors may use the hydrocarbons N-butane, isobutane, propane, or heptane, or other solvents or gases exhibiting low to minimal potential human health-related toxicity approved by WSLCB. These solvents must be of at least 99% purity and a processor must use them in a professional-grade closed-loop extraction system designed to recover the solvents and work in an environment with proper ventilation, controlling all sources of ignition where an inflammable atmosphere is or may be present.

It is required that solvent-based extracts using hydrocarbon gases undergo residual solvent testing. Extracts made from food grade ethanol, glycerin, propylene glycol, or CO2 of at least 99% purity do not require residual solvent testing. Please see the table below, drawn from the WAC 314-55-102, for the list of residual solvents for which we test as well as the ppm at which samples will fail quality assurance testing for each specified residual solvent.