Researchers say they have validated an Electronic REference To access In vivo Concentrations (ERETIC)-based method for rapidly and simultaneously measuring five major cannabinoids in marijuana extracts without derivatization or physical reference standards.
The study, published in Magnetic Resonance in Chemistry, established a quantitative proton nuclear magnetic resonance (¹H-NMR) method for analyzing tetrahydrocannabinolic acid (THCA), cannabidiolic acid (CBDA), delta-9 THC, cannabidiol (CBD) and cannabinol (CBN).
Traditional chromatographic methods used for cannabinoid testing can involve lengthy procedures, depend on multiple reference standards and sometimes cause acidic cannabinoids to convert into their neutral forms during analysis. According to the researchers, those limitations can complicate efforts to accurately determine the chemical composition of marijuana products.
The new method uses diagnostic signals located in portions of the NMR spectrum that are free from interference, allowing multiple acidic and neutral cannabinoids to be quantified during the same analysis.
Researchers compared two calibration strategies: one using butylated hydroxytoluene (BHT) as an internal standard and another using ERETIC calibration, which generates an electronic reference signal rather than requiring a physical standard to be added to each sample.
Both approaches demonstrated strong analytical performance. The method produced relative standard deviations below 5%, indicating high precision, while recovery rates ranged from 97% to 102%, demonstrating strong accuracy. The method’s detection limit was approximately 0.07 milligrams per milliliter.
The ERETIC approach performed particularly well, producing results equivalent to traditional internal-standard calibration while eliminating the need for physical cannabinoid reference standards.
Researchers also successfully used the method to classify marijuana extracts according to their THC-to-CBD ratios, confirming that it could be applied to distinguish between different chemical varieties, or chemotypes, of the plant.
The findings indicate that ERETIC-based NMR testing could provide laboratories with a faster and more efficient alternative for comprehensive cannabinoid analysis.
“The ERETIC-based NMR approach provides a rapid and reproducible alternative for comprehensive cannabinoid quantification without derivatization,” the researchers concluded.
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