Analysis of Cannabinoids in Cannabis Plant Materials and Edible Products Using UltraPerformance Liquid Chromatography (UPLC) with PDA and Mass Detection

Importance of the Topic

The growing legalization of cannabis for medicinal and adult use drives the need for rapid, accurate, and reliable analytical techniques to verify label claims, ensure consumer safety, and maintain product quality. UltraPerformance Liquid Chromatography (UPLC) combined with photodiode array (PDA) and mass detection provides a streamlined workflow for potency testing of diverse cannabis matrices, including flowers, hemp, concentrates, edibles, and beverages.

Study Objectives and Overview

This application note describes the development and validation of a robust UPLC method with PDA and single-quadrupole mass detection (ACQUITY QDa) to separate, detect, and quantify 18 major and minor cannabinoids within a 10-minute analysis cycle. The study evaluates method performance across multiple matrices, calibration ranges, and regulatory compliance requirements.

Methodology and Instrumentation

Sample Preparation

• Flower and Hemp: 0.5 g sample extracted with acetonitrile using Geno/Grinder®, sonication, centrifugation, filtration, and appropriate dilutions (80× and 2000×).
• Edibles: Homogenized sample mixed with water, acetonitrile, and QuEChERS salts; vortexed, centrifuged; extract injected or further diluted.
• Infused Beverages: 10 mL beverage diluted with acetonitrile and QuEChERS salts; centrifugation and direct injection of the supernatant.

Instrumentation

• UPLC System: Waters ACQUITY UPLC H-Class with CORTECS C18 column (1.6 µm, 2.1×150 mm) at 29 °C, 0.45 mL/min flow, 1 µL injection.
• Detection: PDA at 228 nm and 253 nm plus full spectrum (210–400 nm); ACQUITY QDa mass detector in ESI+ and ESI– modes, SIR acquisition (100–600 Da).
• Software: Empower Chromatography Data Software for data acquisition, peak identification, custom calculations, and reporting.

Main Results and Discussion

Separation and Linearity

• Eighteen cannabinoids were fully resolved in <10 minutes, with retention times matched to standards.
• Calibration curves exhibited strong linearity (R2>0.99) over 3.125–50 µg/mL (PDA) and 0.4–50 µg/mL (QDa).

Limits of Detection and Quantitation

• PDA LOD ~3.125 µg/mL; QDa LOD ~0.4 µg/mL, demonstrating enhanced sensitivity for low-level analytes with mass detection.

Matrix Recovery and Accuracy

• QuEChERS extraction in gummy matrices yielded recoveries of 60–125% by PDA and 94–106% by QDa.
• Label-claim comparisons across flowers, edibles, and beverages showed measured potency within 53–125% of declared values.

Peak Identification

• Combination of retention time, UV spectra, and SIR channels improved confidence and minimized false positives in complex samples.

Benefits and Practical Applications

• Rapid throughput (<10 min per run) for high-volume QC laboratories.
• Orthogonal confirmation of identity and quantitation via PDA and mass detection.
• Wide dynamic range to accommodate major and minor cannabinoids.
• Streamlined data management and reporting within Empower CDS.

Future Trends and Opportunities

• Expansion to additional minor cannabinoids and degradation products.
• Integration with automation for sample prep and high-throughput screening.
• Adoption of higher-resolution mass detectors for structural elucidation.
• Real-time in-line monitoring during manufacturing processes.
• Miniaturized and portable systems for field or point-of-use testing.

Conclusion

The Waters ACQUITY UPLC H-Class-PDA-QDa platform delivers a fast, reliable, and sensitive workflow for comprehensive quantitation of 18 cannabinoids across diverse cannabis matrices. The method’s robustness, combined with Empower software capabilities and effective sample preparation, supports regulatory compliance and quality assurance in both industrial and research settings.

References

1. Aubin AJ, Layton C, Helmueller C. Separation of 16 Cannabinoids in Cannabis Flower and Extracts using a Reversed-Phase Isocratic HPLC Method. Waters Application Note, 2018.
2. Dubrow GA, Pawar RS, Srigley C, Sam JF, Talavera C, Parker CH, Noonan GO. A Survey of Cannabinoids and Toxic Elements in Hemp-Derived Products from the United States Marketplace. Journal of Food Composition and Analysis 97 (2021) 103800.