Validation of a LC-DAD-ESI/MS/MS method for the accurate measurement of THC and THCA-A among twenty cannabinoids in various products of Cannabis

Cannabis is a cosmopolitan species that is well known to produce cannabinoids. It has two primary species commonly known as hemp and marijuana. Marijuana is a psychotropic drug because of THC, a heat-triggered decomposition product of THCA-A that is biosynthesized in the fresh plant. Hemp, which is used to produce many consumer products, from fibers to edibles, is characterized by low levels of THC and high levels of CBD, a non/antipsychoactive compound with recently accepted medical use.

Cannabis plants exert psychotropic effects when THC concentration approximates 1%. In the Federal Controlled Substance Act of 1970, cannabis was defined as a Schedule 1 substance, which made cultivation and use of marijuana and hemp illegal. Nevertheless, recently 11 states and the District of Columbia have passed recreational marijuana laws, while 34 states and the District of Columbia have passed medical marijuana laws. In December 2018, Congress enacted the 2018 Farm Bill, which amended the statutory definition of cannabis to exclude hemp, with a THC concentration of not more than 0.3% on a dry-weight basis.

Currently, there is an urgent need for validated methods to measure the total THC concentration in various products of cannabis by crime laboratories. The currently available GC-MS method is unable to directly measure the precursor of THC, i.e. THCA-A, due to its nonquantitative thermal decomposition under GC-MS conditions. Conversely, many liquid chromatography-diode array detector (LC-DAD) and liquid chromatography-electrospray ionization/tandem mass spectrometry (LC-ESI/MS/MS) methods have been published lately, because the LC separation can avoid thermal stress so that acidic cannabinoids can be directly analyzed. However, drawbacks of these methods include limited applicability, insufficient selectivity, flawed recovery experiments, and rare consideration of matrix effect. This proposal seeks to validate a LC-DAD-ESI/MS/MS method, which is based on our recently developed LC-ESI/MS/MS method for the simultaneous measurement of 20 cannabinoids in dried hemp flowers For the accurate measurement of THC and THCA-A among 20 cannabinoids in a wide variety of cannabis products (such as dried flowers, concentrates, edibles and topical products), a total of 68 different types of sample will be used, with key characteristics including broad applicability, maximum selectivity, novel and specially designed recovery experiments, and best consideration of matrix effect. The method will be easily adopted by crime laboratories with different instrumentation, because it will be easily dissected after our comprehensive study, e.g., a liquid chromatography-ultra violet (LC-UV) method using traditional UV detection, an LC-ESI/MS method using a single quadrupole, or an LC-ESI/MS/MS method using a triple quadrupole.

[THC references are edited due to system ability to portray special characters.]

Note: This project contains a research and/or development component, as defined in applicable law, and complies with Part 200 Uniform Requirements - 2 CFR 200.210(a)(14). CA/NCF