Evaluation of a Delta-9-Tetrahydrocannabinol Carboxylic Acid (Δ9-THC-COOH) Immunoassay and a Gas Chromatography-Mass Spectrometry (GC-MS) Method for the Detection of Delta-8-Tetrahydrocannabinol Carboxylic Acid (Δ8-THC-COOH).

Creator(s)

Serena N. Baird
C. Clinton Frazee III, Children's Mercy HospitalFollow
Uttam Garg, Children's Mercy HospitalFollow

Document Type

Article

Publication Date

7-5-2023

Identifier

DOI: 10.1093/jalm/jfad017

Abstract

BACKGROUND: Delta-8 tetrahydrocannabinol (Δ8-THC) is a naturally occurring or synthetically prepared cannabinoid that elicits psychological and physiological experiences commonly reported for its more infamous isomer, delta-9 tetrahydrocannabinol (Δ9-THC). Unlike Δ9-THC, Δ8-THC products are generally legal under federal law and there has been a rise in their usage. One of the main targets for detection and quantitation of Δ9-THC is its inactive metabolite, 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (Δ9-THC-COOH).

METHODS: This study evaluated the ability of the currently used Δ9-THC-COOH immunoassay and gas chromatography-mass spectrometry (GC-MS) methods to detect 11-nor-9-carboxy-Δ8-tetrahydrocannabinol (Δ8-THC-COOH) and distinguish it from Δ9-THC-COOH.

RESULTS: The EMIT II Plus® Cannabinoid immunoassay for Δ9-THC-COOH with a cutoff of 20 ng/mL showed positive results for Δ8-THC-COOH with concentrations of 30 ng/mL or higher. Although many of the ion fragments generated by mass spectrometry were found to overlap between the 2 compounds, the GC-MS method presently used to quantify Δ9-THC-COOH separated the 2 compounds sufficiently to identify them independently by relative retention time.

CONCLUSION: Current immunoassays and GC-MS methods should be evaluated for the ability to detect and distinguish the presence of Δ8-THC-COOH.

Journal Title

J Appl Lab Med

Volume

8

Issue

4

First Page

665

Last Page

673

MeSH Keywords

Humans; Dronabinol; Gas Chromatography-Mass Spectrometry; Substance Abuse Detection; Cannabinoids; Immunoassay; Carboxylic Acids

Keywords

Dronabinol; Gas Chromatography-Mass Spectrometry; Substance Abuse Detection; Cannabinoids; Immunoassay; Carboxylic Acids

Recommended Citation

Baird SN, Frazee CC, Garg U. Evaluation of a Delta-9-Tetrahydrocannabinol Carboxylic Acid (Δ9-THC-COOH) Immunoassay and a Gas Chromatography-Mass Spectrometry (GC-MS) Method for the Detection of Delta-8-Tetrahydrocannabinol Carboxylic Acid (Δ8-THC-COOH). J Appl Lab Med. 2023;8(4):665-673. doi:10.1093/jalm/jfad017