This paper describes the development of a new procedure for hemp sample preparation that consists of grinding, extraction, and clean-up steps, which can be completed within a timeframe of 15 minutes, for a total sample analysis of less-than 30 minutes for the liquid chromatography with photodiode array detection (LC-PDA) method.
The current study describes a new sample preparation procedure consisting of grinding, extraction, and clean-up steps that can be completed in a maximum time of 15 min. When combined with the previously reported LC-PDA method, the total sample analysis time has been reduced to less than 30 min. Previously characterized hemp samples from the NIST Cannabis Quality Assurance Program (CannaQAP) were used to compare the performance of each procedure [23].
Before the passage of the Agriculture Improvement Act of 2018, more commonly referred to as the 2018 Farm Bill, forensic laboratories were only required to perform qualitative measurements to confirm the identity of seized plant samples as Cannabis sativa (hemp or marijuana). The new law defines hemp at a federal level as Cannabis sativa containing 0.3 percent or less Δ9-THC. Because forensic laboratories were not adequately equipped with the proper methods or training to meet these requirements, significant backlogs in casework resulted. The National Institute of Standards and Technology (NIST) responded by providing analytical tools to the forensic community. An accurate and precise method was previously developed to determine Δ9-THC, Δ9-THCA, and total Δ9-THC in botanical samples based on liquid chromatography with photodiode array detection (LC-PDA). Cannabis plant samples were ground and extracted with methanol using routine laboratory equipment. The original sample preparation procedure was time-consuming, taking over 70 min. The method described here has been optimized with the time required for sample preparation and LC-PDA analysis has been reduced to less than 30 min. (Published Abstract Provided)