Cannabis sativa L. is an herbaceous flowering plant that has garnered attention as a new frontier in modern medicine, based on the presence of various classes of therapeutic phytochemicals, including bioactive cannabinoids (tetrahydrocannabinol [THC] and cannabidiol [CBD]), fragrant terpenes (such as α- and β-pinene), and anti-oxidant flavonoids (for example, anthocyanins). These phytoconstituents can help remedy neurological disorders, metabolic abnormalities, sleep irregularities, and cardiovascular conditions, among others. However, cannabis is not always readily accessible to the general public, since it is still classified as a Schedule I narcotic at the federal level. In states like Texas, with a narrowly-focused medicinal program, access to cannabis medicines is prohibited, unless you are dealing with one of a small subset of medical afflictions, such as epilepsy, that warrant a medical patient card.
Nonetheless, cannabis retail stores have found ways to circumvent these restrictions, though this is potentially dangerous for end users and can also cause chaos for law enforcement. These “avenues of circumvention” include the widespread proliferation of gray-area products, such as those containing Δ8-THC and other unregulated and synthetic cannabinoids (including THC-O), as well as products marketed as THCA flower. Confounding the control of these products is the lack of appropriate analytical tests performed by forensic toxicology laboratories; their tests are meant to detect Δ9-THC use but do not consider the potential for exposure to Δ9-THC from unregulated products.
Genetically, the relative expression of Δ9-THC (or just THC) and CBD, and their corresponding THCA and CBDA precursors, is essentially what defines a cannabis plant as either a restricted high-THC medicinal cannabis product or a widely accessible hemp product. The 2018 Farm Bill helped define this point of differentiation, with percentages of total THC (Δ9-THC + 87.7% of Δ9-THCA to account for weight post-decarboxylation) above and below 0.3% w/w constituting high-THC cannabis and hemp, respectively. This defining threshold does not account for some of the other naturally occurring and psychoactive cannabinoids, such as Δ8-THC, which leaves opportunities for circumvention. Δ8-THC is generally reported to exhibit about half the psychoactive effect of Δ9-THC for a similar dosage.
A general aspect of the consumption of cannabinoids is that they are lipophilic and will accumulate and remain in the body, detectable for many days after end use. Those who consume widely available CBD products may actually be exposed to small amounts of Δ9-THC. Consumers who undergo regular drug testing in their workplace should be wary of taking “full spectrum” CBD products. These products likely have the highest therapeutic benefit, since they can contain a range of cannabinoids and terpenes. They also likely contain a small amount of Δ9-THC. Prolonged use of a full spectrum CBD product could result in the accumulation of Δ9-THC in the body, which could ultimately lead to a failed drug test.
The widespread sale of Δ8-THC products can be found in states that have not legalized high THC cannabis. A majority of Δ8-THC products are not comprised of naturally derived Δ8-THC. This isomer is generally present at a fraction of a percent of natural abundance in hemp and cannabis flowers. Rather, Δ8-THC is synthesized by chemically treating CBD. The problem with this practice is that the conversion of CBD into Δ8-THC also results in the production of a quantifiable amount of Δ9-THC as a reaction byproduct that likely goes unadvertised to end users. Again, significant or prolonged use of Δ8-THC products could result in the accumulation of Δ9-THC in the body, which would be cause for concern if drug testing was performed.
Efforts to circumvent cannabis regulations are causing chaos for retail customers and law enforcement alike. Potentially or even clearly illegal products are able to be purchased under the guise of a legal/gray area, such as in the lack of regulation of Δ8-THC. Unfortunately, neither the customer nor the purveyor are unable to plead ignorance when said products are confiscated, tested, and deemed non-conforming. Retail customers that become involved in traffic violations where blood toxicology samples are collected could be subjected to the presence of incriminating Δ9-THC metabolites in their blood, unbeknownst to them. This presents a major issue for all parties involved.
To make matters worse, many forensic laboratories have not demonstrated the ability of their testing methods to distinguish Δ8-THC from Δ9-THC. Though this type of separation can be made, if a method has not been designed to discriminate these isomers, it may lack the ability to do so. Even those forensic laboratories that try to show discrimination of Δ9- and Δ8-THC in their testing methodology do not attempt to monitor metabolites of Δ8-THC metabolites, as they do for Δ9-THC. Again, it is unclear whether methods can distinguish such isomeric metabolites, especially if no attempt is made to do so during method validation.
Another seemingly gray area is not so gray. In states where high-THC cannabis is not legal, some purveyors are selling a product called THCA flower. Remember, the point of differentiation between highly regulated medicinal or recreational high-THC cannabis and hemp is 0.3% total Δ9-THC, which includes the post-decarboxylation weight of Δ9-THCA. Somehow, for reasons we don’t fully understand, THCA flower is not “hot” or non-complying hemp, and it is apparently not being considered high-THC cannabis. This practice seems egregiously flawed, considering that THCA is converted into THC upon heat-induced decarboxylation. In other words, if the THCA flower product sold is greater than approximately 0.35% w/w concentration THCA, then it is technically high-THC cannabis. The consumption of THCA flower products will undoubtedly result in surprising blood analysis results. Even beyond the situation of a traffic violation or accident, it is easy to envision scenarios where one’s employment trajectory may be negatively impacted by unwanted metabolites being present in either a blood or urine sample.
The gray areas are not made clearer when forensic blood testing is performed. As mentioned, some legal use of hemp or hemp-derived products could result in positive blood tests for Δ9-THC and its metabolites. Forensics labs do not generally test for CBD and its metabolites; most also do not test for Δ8-THC and its metabolites. Thus, instead of having clear evidence of the nature of the products ingested through the application of more thorough blood testing, those found with any amount of Δ9-THC in their body are prosecuted as criminals. Once prosecution is involved, successfully navigating the gray area will depend on the ability of defense counsel to argue the innocence of the individual. Currently, it is our experience that there are few defense attorneys who understand the intricacies of the current cannabis and hemp consumer market and the perils it can have for individuals and their freedoms.
Zacariah L. Hildenbrand, PhD is a partner of Medusa Analytical. He sits on the scientific advisory board of the Collaborative Laboratories for Environmental Analysis and Remediation (CLEAR), is a director of the Curtis Mathes Corporation (OTC:TLED), and is a research professor at the University of Texas at El Paso, USA. Hildenbrand’s research has produced more than 70 peer-reviewed scientific journal articles and textbook chapters. He is regarded as an expert in point source attribution, forensics analysis, and has participated in some of the highest profile oil and gas contamination cases across the United States. Direct correspondence to: zac@medusaanalytical.com
Melissa Giguere, DFS is an independent consultant for forensic toxicology and provides expert testimony as an affiliate of Medusa Analytical. Melissa earned a Doctor of Forensic Science (DFS) degree, with a focus on toxicology, from Oklahoma State University. Her background includes over ten years of experience in forensic toxicology as a laboratory analyst. She is proficient in multiple areas of instrumentation, extraction techniques, and evidence handling, and held a Texas Forensic Science Commission license. Her background also includes over 13 years of law enforcement experience, ranging from serving as a Master Certified Jailer to holding a Commissioned Peace Officer certificate in the State of Texas.
Kevin A. Schug, PhD is a full professor and Shimadzu Distinguished Professor of Analytical Chemistry in the Department of Chemistry and Biochemistry at The University of Texas at Arlington and a partner of Medusa Analytical. He joined the faculty at UT Arlington in 2005 after completing a PhD in chemistry at Virginia Tech under the direction of Harold M. McNair and a postdoctoral fellowship at the University of Vienna under Wolfgang Lindner. Research in the Schug group spans fundamental and applied areas of separation science and mass spectrometry. Schug was named the LCGC Emerging Leader in Chromatography in 2009, and most recently has been awarded the Silver Jubilee medal by The Chromatographic Society (UK) in 2024. Direct correspondence to: kschug@uta.edu
The LCGC Blog: A Simplified Guide for Weighted Fitting and its Significance in Separation Science
June 2nd 2025In this month's edition of the LCGC Blog, discover how weighted least squares regression enhances quantitation accuracy in analytical chemistry, particularly for low-concentration analytes in HPLC.
