Orange Photonics (Elkins, NH) introduced a unique spectroscopic accessory called Terpene+ to add terpenes to the list of analytes assayed with the LightLab cannabis analyzer. Terpene content of cannabis is an important quality attribute related to taste for the recreational market segment. Plus, anecdotal reports claim that the terpenes are also important in the medicinal market segment. However, the Schedule I classification of cannabis has impeded rigorous investigation of these reports.
With the Terpene+ upgrade, the content of monoterpenes, such as myrcene, limonene, and alpha-pinene, is recorded spectroscopically. Typically these account for 80% of the total terpenes. Sesquiterpenes are the other major class in cannabis plants. With the LightLab, these are not assayed directly. This simplifies many applications since monoterpenes and sesquiterpenes often have a fixed ratio (~4:1). The exception seems to be attributed to warm drying of the vines after harvest, or peculiar cultivars. Monoterpenes (C5H8) are much more volatile than sesquiterpenes (C15H24) so the monos are lost preferentially to the C15 compounds. With cold drying protocols, which takes longer, the loss of C5s is much less significant.
The basic LightLab is a liquid chromatograph (Figure 1) with three fixed-wavelength absorbance detectors optimized for assay of the common cannabinoids including D9-tetrahydrocannabinol, tetrahydrocannabinoilic acid, cannabidiol, cannabidiolic acid cannabinol, and cannabigerolic acid (Figure 2). The isocratic run time is 8 minutes. The instrument weighs only 8 lb, including a rechargeable battery, which is sufficient for 8 hr of operation.
Figure 1 – A chemist injects a sample of cannabis extract into the LightLab portable cannabis analyzer, which uses liquid chromatography for the separation and analysis of cannabinoids. Run time is 8 minutes.
Figure 2 – Typical report from the LightLab cannabis analyzer. Content of specific cannabinoids is reported along with estimate of total terpene content (high, medium, or low) based on response of the monoterpene class.Support reagents, including mobile phase, are provided in a kit form with sufficient mobile phase, column, and supplies for 25 samples. The kit is designed for use by people with no prior chromatography experience or training. A sample is extracted and filtered; then a 3-mL aliquot is transferred to the injector, which overfills the sample loop. The isocratic run is complete in 8 minutes. The output is digital and definitively not a chromatogram that would be difficult for the naïve user to interpret.
Orange Photonics was founded in 2015. Dylan Wilks is the chief technical officer and co-founder (see Figure 3). His grandfather was Paul Wilks (see Figure 4), a noted infrared spectroscopist and president of Wilks Scientific, who has been recognized as a Heritage Award Honoree at Pittcon.
Figure 3 – Dylan Wilks working with prototype of a LightLab instrument.
Figure 4 – Paul Wilks (~1965).Robert L. Stevenson, Ph.D., is Editor Emeritus, American Laboratory/Labcompare; e-mail: [email protected]