The chemical compositions of by-products from commercial cannabidiol (CBD) extraction were characterized and quantitated by employing gas chromatography mass spectrometry (GC-MS) and GC flame-ionization detection (GC-FID). The four major by-products included an ethanol-wax suspension (WAX), terpenoid distillate (DIST-A), tar-like residue (TAR), and red resin (RES). The composition of WAX consisted of ∼28 wt % n-alkanes and ∼33-38 wt % cannabidiolic acid and CBD combined. The DIST-A consisted of ∼40 wt % sesquiterpenoids and ∼58 wt % cannabinoids. The DIST-A terpenoid profile was compared to dried unprocessed inflorescences (HEMP) to observe changes in monoterpene content after the distillation process. The TAR was composed of ∼5-9 wt % higher n-alkanes and up to 91 wt % cannabinoids, while RES consisted of up to 99 wt % cannabinoids. Several impurities including cannabidibutol and dehydroabietic acid were identified in commercial CBD samples. Compositional information of these by-products may provide manufacturers with the opportunity to optimize processing conditions.
Keywords: cannabidiol; cannabinoids; chemical characterization; manufacturing by-products.