Eight Cannabinoids by HPLC-UV
Measurement of cannabinoid content, or “the potency test”, is frequently discussed in cannabis analysis. Many such methods have been developed in the past few years, but none have yet been rigorously validated and shown to work consistently with real cannabis samples of all types. Consequently, labs testing cannabis are each using different methods of analysis, and no standardized method has been universally adopted.
A recent study on Scientific Reports of the Washington state I-502 dataset has highlighted the need for lab standardization. Consistently measuring low levels of CBD in the presence of large levels of other cannabinoids is not something that all labs appear capable of. In the interests of lab standardization, we are releasing our cannabinoid analysis method into the public domain: Method Application Note – Eight Cannabinoids by HPLC-UV.
In this paper, we describe the method which has been in routine use at Confidence Analytics since 2014, measuring CBDA, CBGA, THCA, CBG, CBD, CBN, THC (delta-9), and CBC. It has acquired data on over 50,000 cannabis consumer products in that time. We include example instructions for sample preparation (including our recommended means of homogenizing flower samples), instrument selection and performance, important considerations, and an overview of our experience using this method for years.
Robustness
This method performs excellently for all cannabis flowers and concentrates. The use of a high-organic-fraction LC pump program affords useful resolution between matrix components of cannabis-infused products and the target analytes for most sample types. Adequate sample preparation removes most lipids from vial solutions. Beverages, liquid emulsions, hard candies, dairy-containing candies, gummies, baked goods, cooking oils, and salty snacks are all handled deftly by this method. Analyte retention times are essentially unaffected by various sample matrices.
Beyond The Method
As with anything in life, you only get back what you put in. Simply following the steps will not be sufficient to guarantee success. Diligence is required across all aspects of lab operations from sample intake and handling to processing, post-processing, quality assurance and more. We attribute much of our success to the care and attention our entire team takes with the samples we receive. We also pride ourselves on the customer service we deliver, regularly going beyond analysis to help our clients solve problems. This is how we expand robustness beyond our methods to our entire lab.
Moving Forward
By agreeing to a common and transparent set of standards for cannabinoid analysis in Washington state, we can work towards eliminating the differences between labs that are readily apparent to everyone in the industry. By releasing our method into the public domain, we hope to advance the standardization conversation – who will join us?