HPLC Method for Better Separation of THC Isomers to Ensure Safety and Compliance in the Hemp Market.

The 2018 Farm Bill dictates that delta-9-tetrahydrocannabinol (Δ 9 -THC) concentrations must not exceed 0.3% in hemp and hemp-derived products in order to be "compliant." This narrow margin of error necessitates very precise testing methods throughout every facet of the hemp industry. Though gas chromatography has become the industry's gold standard, many hemp laboratories still use high-performance liquid chromatography (HPLC) to quantify cannabinoids, and thus there exists a need for HPLC methods that can separate delta-8-tetrahydrocannabinol (Δ 8 -THC) and Δ 9 -THC-a notoriously difficult task. This article details one such method, while simultaneously acknowledging the inevitable limits of using HPLC to separate cannabinoids. The method was also used to test Δ 8 -THC samples that were marketed as compliant, and it was found that all of the samples contained well over 0.3% Δ 9 -THC. The use of refined testing methodologies is crucial for hemp companies to ensure compliance, prevent adverse health effects, and provide consumers with accurate cannabinoid profiles of the products that they purchase.