Researchers have developed a low-cost method for measuring cannabidiol (CBD) that could provide laboratories with an alternative when more expensive testing equipment is unavailable.

The findings are presented in a study that’s published in the Journal of Cannabis Research and conducted by researchers affiliated with the University of Buenos Aires and Argentina’s National Scientific and Technical Research Council.

For the study, researchers adapted the Beam reaction, a traditional color-based test used to identify CBD, into a quantitative technique capable of measuring the cannabinoid’s concentration. The method uses UV-Vis spectrophotometry and relies on a chemical reaction between CBD or cannabidiolic acid (CBDA) and a 5% ethanolic potassium hydroxide solution. The reaction produces a colored compound that can be measured based on how it absorbs light.

Testing identified a maximum absorbance peak at 530 nanometers. Researchers found that the reaction stabilized after a 24-hour incubation period, allowing samples to be analyzed in batches with consistent results.

The optimized method demonstrated a high degree of linearity, meaning the measured absorbance closely corresponded with CBD concentration. It also produced relative standard deviations of 2.88% for tests conducted within the same day and 4.74% for tests conducted on different days.

Researchers reported a detection limit of 1.84 micrograms per milliliter and a quantification limit of 5.58 micrograms per milliliter.

High-performance liquid chromatography, commonly known as HPLC, is widely used to identify and quantify cannabinoids but requires specialized and often costly equipment. The newly developed method uses readily available reagents and standard laboratory instruments, potentially making CBD testing more accessible to smaller laboratories and research centers.

“The findings validate the Beam reaction as a precise, simple, and economically viable tool for the quantification of total CBD,” researchers concluded.