Editor’s note: Cannabis Business Times’ November cover story examined the prevalence and problems of lab shopping and potency inflation in the cannabis industry. As part of that coverage, CBT asked Florida-based ACS Laboratory, which tests the state’s medical cannabis and has hemp clients in 48 states, more about what cannabis potency testing involves. Here, Roger Brown, founder and president of ACS Laboratory, delves into the process of how the company tests cannabis for THC potency.
If you work for a cannabis or hemp testing lab, refer to your state’s testing regulations to ensure compliance.
Figure 1. Step 1: Flower is ground and placed in a sterile cup for weighing and prep. Step 2: Sample is weighed and placed in a glass vial.
Figure 2. Step 3: Solution is added, and the vial is sealed. Then the sample vial goes to a grinder for flower or a vortexer for derivatives.
A grinder is specifically designed for vigorous up and down shaking to facilitate even distribution of the material.
Vortexers or vortex mixers are a critical piece of laboratory equipment used to mix small vials of samples rapidly in a quickly oscillating circular motion. There are specific types of suspension that can only be done by creating a vortex, rather than just shaking a sample. For instance, a vortex mixer is able to mix viscous samples that would otherwise stay unblended. If you need to mix oil and water, a vortex mixer is the equipment you want to get the job done right.
Step 4: For both flower and derivatives, the sample goes to a sonicator. Sonicators use ultrasonic frequency to help mix or dissolve samples during preparation.
Step 5: After sonicating samples, samples are placed back in the vortexer to make sure analytes, or the cannabinoids being tested, are not stuck in the bottom or trapped inside.
Step 6: Flower and derivatives go to a centrifuge. Centrifuges allow labs to separate samples quickly and accurately to maximize the efficiency of cannabis testing. A centrifuge is used to separate particles suspended in a liquid according to particle size and density, viscosity of the medium, and rotor speed. Within a solution, gravitational force will cause particles of higher density than the solvent to sink, and those less dense than the solvent to float to the top.
Figure 3. Step 7: A potency dilution is made according to the testing panel requested and/or target range of values. Dilution, which makes a high-concentrated solution into a less concentrated solution, is a sample preparation step. Samples are diluted with diluent to the calibration range that instruments are validated for.
Figure 4. Step 8: Liquid chromatography instrumentation is used for analytical testing. The lab creates a batch file, which is a sequence file containing information about samples, such as weight, dilution and identification; as well as quality controls such as the standards curve; and the curves’ positions for instruments that the lab uses. The vials/plates for the batch are then loaded onto instruments like the high-performance liquid chromatography with UV detection (LCUV) or liquid chromatography–mass spectrometry (LCMS). Step 9: The data is processed, the components of the sample go through the process of chromatography to separate them so the individual components, i.e. individual cannabinoids, can be measured and analyzed. The presence and amount of the targeted cannabinoid’s concentration is then identified and measured using a calibration curve. Below is an example of chromatography of a potency assay, which details the ratios and presence of active cannabinoids against a certified reference material. Certified reference materials (CRMs) are controls or standards used to check the quality and metrological traceability of products, to validate analytical measurement methods, or for the calibration of instruments.
Figure 5. Step 10: A certificate of analysis (COA) is produced and verified by a trained quality control personnel before its release to clients. A sample COA:
Roger Brown co-founded the first cannabis testing lab in Florida, ACS Laboratory. ACS Laboratory is ISO/IEC 17025:2017 accredited, DEA licensed, and CLIA licensed with the largest state-of-the-art facility in the eastern USA. The Most Trusted Cannabis and Hemp Laboratory in the USA™, ACS Laboratory has increased its reach to 50 states and Puerto Rico, and 16 countries worldwide.