The cannabis plant consists of a large variety of chemicals and compounds. Approximately 140 belong to a class of aromatic organic hydrocarbons known as terpenes. Terpenes, which are produced in the trichome of the bud, are responsible for the numerous aromas and flavors of the cannabis plant. Beyond fragrance, terpenes have also been shown to serve medicinal and therapeutic purposes. For example, the terpene beta-caryophyllene, also found in basil, oregeno, and black pepper, has been shown to have anti-inflammatory, antioxidant, and pain-relieving benefits. In other clinical models, linalool showed anti-seizure and anti-epileptic effects. Current research has only scratched the surface about the roles of terpenes and flavinoids and how they may be harnessed for novel pharmaceuticals for both physical and mental therapies.

The important psychoactive component in marijuana is tetrahydrocannabinol (THC), and is therefore the primary interest of potency testing. THC/CBD ratio is also relevant for therapeutic value and labeling laws. Cannabis plant material contains THC-A which is the non-psychoactive, carboxylic acid form of THC. Because THC-A becomes THC upon heating, it’s common for many labs to use HPLC for testing cannabis edibles and liquids, as they may be tested at room temperature. HPLC can identify THC Acid (THCA) and CBD acid (CBDA), while gas chromatography cannot (without derivitization). However, GC is considered a simpler and faster approach. For routine identification, especially for raw materials that are destined for heated consumption, GC-FID is ideal, but for positive identification of each cannabinoid, GC-MS is recommended.

In addition to terpene and potency profiles, there is a huge demand for laboratories to identify a wide variety of contaminants. Although no pesticide product is federally-registered for use on cannabis, in various states they may be used provided they meet certain criteria. A pesticide product can legally be applied to cannabis under state law if the active ingredients found in the product are exempt from residue tolerance requirements and the product is either exempt from registration requirements or registered for a use that is broad enough to include use on cannabis. Residue tolerance requirements are set by U.S. EPA for each pesticide on each food crop and are the amount of pesticide residue allowed to remain in or on each treated crop with “reasonable certainty of no harm.” Some pesticides are exempt from the tolerance requirement when they are found to be minimal risk. States also set individual action limits for pesticides used on cannabis

The growing use of vaporizers, combined with the market in electronic cigarettes, has created huge demand for “vaping” oils. There are a number of ways to extract cannabis oil from dry products. Some concentrated forms of cannabis oil, utilize butane (butane hash oil or BHO), heptane, propane, glycerin, and ethanol as an extraction solvent. This poses a clear concern for consumers. Regulators in most States now require all solvent-extracted cannabis concentrates to be tested for residual solvents.