Innovative Framework for Blinded Evaluation of Methods: Application to Cannabinoid Quantification in Hemp

Area of Science:

• Analytical Chemistry
• Pharmacognosy
• Forensic Chemistry

Background:

• Increased demand for hemp-derived products necessitates reliable cannabinoid quantification methods.
• Regulatory changes impact the landscape of hemp product analysis.
• Accurate cannabinoid measurement is crucial for product quality and safety.

Purpose of the Study:

• To systematically evaluate a liquid chromatography photo-diode array (LC-PDA) method for quantifying 11 cannabinoids in hemp.
• To assess method performance using a blinded collaborative framework with both fortified and endogenous analytes.
• To verify method suitability for routine hemp testing in a new laboratory setting.

Main Methods:

• A previously validated LC-PDA method was implemented and verified at a new laboratory (VMDL).
• A two-round blinded method test (BMT) was conducted with blind-coded samples of hemp, nettle, and mixtures.
• External calibration (EC) was used for quantification, with parallelism evaluation and standard-addition calibration applied to address matrix effects and accuracy for endogenous cannabinoids.

Main Results:

• The LC-PDA method demonstrated good linearity, accuracy, and precision for fortified samples across various matrices using EC.
• Parallelism testing supported the use of solvent-based EC for endogenous cannabinoids in hemp.
• Standard-addition estimates showed directional consistency with EC but indicated potential differences (15-45%) for some analytes, highlighting the need for extraction efficiency assessment.

Conclusions:

• The collaborative framework, integrating multiple matrices and complementary quantification approaches, enhances method validation.
• The evaluated LC-PDA method is suitable for routine hemp testing at VMDL.
• Further characterization of extraction efficiency for incurred versus fortified cannabinoids in complex botanical matrices is essential for robust accuracy assessment.