A Fast, Comprehensive and Accurate Quantitative Assay of 16 Cannabinoids in Different Matrix by UPLC-PDA
In 2018, AOAC has published a method to quantify 10 cannabinoids (CBDs) with the range of 0.500-10.0 µg/mL in cannabis. However, there are more than 100 CBDs isolated from cannabis in addition to above 10 CBDs. Furthermore, CBDs have been legally and widely used for more and more products. Thus, AOAC method may not cover various needs from different CBDs products. In order to cover various needs, Dyad Labs has developed UPLC-PDA and UPLC-MS/MS methods for 16 major CBDs. In this poster, the fast, comprehensive and accurate quantitative UPLC-PDA assay for 16 CBDs is presented in different matrix. The UPLC-MS/MS method is presented in P-T-018 poster.
Sample Preparation and Extraction:
Appropriate sample was weighed in 50 mL centrifuge tube. 5 mL of DI water was added to hydrate sample. 35 mL of methanol was then added to sample to precipitate protein and other types of interferences. The supernatant is diluted if needed, and then cleaned up with filter. Filtered sample is mixed with equal volume of DI water to match with LC initial solvent before analysis on instrument.
UPLC system: Waters Acquity UPLC System including quaternary solvent manager, sample manager FTN, column manager and PDA detector.
PDA detector: Scanning range of 200 nm to 400 nm. Quantitation uses 220 nm as channel.
Results and Discussions
In AOAC method, the standard solutions are expensive, but only have 3 days stability. In order to understand the stability of CBD better, we comprehensively investigated on the stability of all CBDs with different parameters including light, heat and pH. The study indicated that CBDs are sensitive to light, heat and pH. Neutral condition with light protection and low temperature was adopted during sample preparation.
In order to establish longer stability, we also compared different solvents including water, methanol, acetonitrile and methanol:water (70:30 v/v). The data indicated that CBDs are most stable in methanol:water (70:30 v/v). During validation, we established up to 7 days stability for the standard solutions at 4.00-40.0 ug/mL using methanol:water (70:30 v/v) as solvent in fridge. The extracted sample is stabile for 7 days with storing in fridge.
Sensitivity and Linearity
The curve range of 4.00-40.0 ug/mL was successfully validated. The regression is quadratic with 1/x as the weighing factor. The correlation coefficient R2 is > 0.995. The representative chromatograms of LLOQ and ULOQ were in Figure 5.
Accuracy and Precision
The accuracy and precision were investigated with CBD oil sample and post-spiking CBDs in blank botanical and protein matrix at lower, medium and high regions of the established range of the calibration curve.
This is the first validated method for a fast, comprehensive and accurate quantification of the 16 major CBDs in CBD oil, botanical and protein matrix using UPLC-PDA .