Evaluating Different C18 Columns for the LC Separation of Δ9-THC and Other Related Cannabinoids

Published

June 16, 2026

Author(s)

Walter Wilson

Abstract

The best separation possible of delta-9-tetrahydrocannabinol (Δ9-THC) in complex samples via liquid chromatography (LC) is particularly challenging due to the potential for interference from other cannabinoids. Over 100 cannabinoids have been detected in Cannabis Sativa plant samples. The separation of Δ9-THC in Cannabis-derived finished products was believed to be easier than plant extracts to analyze at one time because the acidic cannabinoids are removed during material preparation. However, the emergence of synthetic or semi-synthetic cannabinoid products, such as delta-8-tetrahydrocannabinol (Δ8-THC), has led to more chromatographic interferences due to the presence of synthetic by-products. The original LC separation method implemented at NIST was not acceptable when these chromatographic interferences are present. Within this context, the work presented here explores the separation of an 11 cannabinoid mixture with different monomeric and polymeric octadecylsilane (C18). Monomeric C18 columns (NexLeaf C18, ACE 3 C18, and ACE Super C18) provided better separations of the 11 cannabinoids, and baseline separations were obtained in less than 13 min after minor adjustments to the mobile phase program. Using the NexLeaf C18 column, mixtures of Δ9-THC and four known chromatographic interferences were analyzed. Cannabinolic acid (CBNA) could not be separated from Δ9-THC; however, CBNA has drastically different absorbance spectra from Δ9-THC, and the co-elution of these cannabinoids can easily be recognized using photodiode array detection. For instances when CBNA is present, the sample can be reanalyzed using an alternate NexLeaf C18 method developed at NIST CSD to baseline resolve Δ9-THC and CBNA in 50 mins.

Citation

Chromatographia

Pub Type

Journals

Download Paper

https://doi.org/10.1007/s10337-026-04498-9

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Keywords

Cannabinoid, Δ-9-Tetrahydrocannabinol, Liquid Chromatography, C18 Columns

Citation

Wilson, W. (2026), Evaluating Different C18 Columns for the LC Separation of Δ9-THC and Other Related Cannabinoids, Chromatographia, [online], https://doi.org/10.1007/s10337-026-04498-9, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=961167 (Accessed June 18, 2026)

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