Inter-Lab Variation in the Cannabis Industry, Part II: Solutions: Page 3 of 3

June 11, 2019
Brian Smith
Brian Smith

Analyzing Samples Quickly

Work in the literature shows that cannabis samples are unstable, some with half-life of just eight months (8-12). Thus, these samples should be analyzed as soon as possible after collection. This means cannabis laboratory clients need to rush samples to the laboratory, and laboratories need to turn around samples as quickly as possible. I realize many laboratories may be swamped with samples, and five-day or even seven-day turn-around times may be common. But this needs to be the exception rather than the rule. The industry needs to invest in the personnel and equipment to speed up analyses so samples are analyzed while they are fresh.

Proper Sample Storage

Since we know cannabis samples are unstable, and until we have further data on ideal storage conditions, all samples collected should be stored in a refrigerator in the dark until they are needed for analysis. State regulators should insist upon this.

Orthogonal Testing

Orthogonal testing means using a second analytical method as a referee for a primary method. For example, it has been shown that mid-infrared spectroscopy can accurately determine cannabinoid and terpene profiles in cannabis distillates and extracts (5,12,13). Side-by-side studies on the same sample set can be used as a sanity check on high-performance liquid chromatography (HPLC) potency methods. If the HPLC suddenly starts disagreeing with the second method, it may indicate that some undetected change in the HPLC method has occurred that needs to be investigated. Some laboratories are already doing this (14).

More and Better Training

At the end of the day our analyses are only as good as the quality of the people performing them. The existence of the inter-laboratory variability problem and my own observations and experience prove to me that we as an industry need to improve the quality of our analysts. This means cannabis laboratories need to invest more time in training their current employees, and hire employees with appropriate degree levels and experience.

To draw the analogy to the pharmaceutical industry, laboratory managers and directors there typically have graduate degrees in analytical chemistry and many years of experience. Given that cannabis is medicine and should be tested like medicine, I strongly feel that laboratory managers and directors in the cannabis industry should have a graduate degree in analytical chemistry and significant experience. Technicians should have appropriate degrees and extensive on-the-job training.

This is another place where state regulators can step up, requiring continuing education for current laboratory employees, and insisting new hires have appropriate educational levels and experiences.


The inter-laboratory variation problem in the cannabis analysis industry is real and threatens the health and safety of consumers and the future of our industry. It has a number of causes, including a lack of standard methods and reference materials. These problems are exacerbated by the lack of marijuana legality at the federal level in the United States. However, there are things the cannabis industry can do now of its own accord to ameliorate the problem including agreeing on standard methods, representative sampling, proper sample storage, orthogonal testing, and more and better training of laboratory personnel. Only if we as an industry acknowledge this problem and begin working on solutions now will our desired goal of widespread legalization ever occur.



  1. B.C. Smith, Cannabis Science and Technology 1(3),10-12 (2018).
  2. B.C. Smith, Cannabis Science and Technology 1(4),12-16 (2018).
  3. B.C. Smith, Cannabis Science and Technology 2(1),14-19 (2019).
  4. B.C. Smith, Cannabis Science and Technology 2(2), 12-17 (2019).
  5. B.C. Smith, P. Lessard, and R. Pearson, Cannabis Science and Technology 2(1), 48-53 (2019).
  6. B. Young, The Seattle Times January 5, 2016.
  8. M. Starks, Marijuana Chemistry (Ronin Publishing, Oakland CA, 1977).
  9. J. Fairbairn, J. Liebmann, and M. Rowan, Journal of Pharmacy and Pharmcacology, 28(1) (1976).
  10. I. Trofin, G. Dabija, D. Vaireanu, and L. Filipescu, Revista de Chimie (Bucharest), 63(293) (2012).
  11. C. Lindholst, Australian Journal of Forensic Sciences 42(181) (2010).
  12. B.C. Smith, Terpenes and Testing, Nov.-Dec. pg. 48 (2017).
  13. B.C. Smith, Terpenes and Testing, Jan.-Feb. pg. 32 (2018).
  14. J. Strull, private communications.


Brian C. Smith, PhD, is Founder, CEO and Chief Technical Officer of Big Sur Scientific in Capitola, California. Dr. Smith has more than 40 years of experience as an industrial analytical chemist having worked for such companies as Xeros, IBM, Waters Associates, and Princeton Instruments. For 20 years he ran Spectros Associates, an analytical chemistry training and consulting firm where he improved their chemical analyses. Dr. Smith has written three books on infrared spectroscopy, and earned a PhD in physical chemistry from Dartmouth College.


How to Cite This Article
B.C. Smith, Cannabis Science and Technology 2(3), 10-14 (2019)