Fast, Easy, and Reliable Monitoring of THCA and CBDA Decarboxylation in Cannabis Flower and Oil Samples Using Infrared Spectroscopy

Importance of the Topic

Decarboxylation is a critical step in cannabis processing that transforms inactive cannabinoid acids (THCA, CBDA) into their neutral, bioactive forms (THC, CBD). Precise control ensures product potency, consistency, and economic efficiency, while avoiding overprocessing that can degrade valuable cannabinoids and terpenes.

Objectives and Study Overview

This study introduces a rapid, on-site infrared spectroscopy method using the Agilent Cary 630 FTIR platform and a DELIC Labs-developed model to monitor THCA and CBDA decarboxylation in cannabis flower and oil. It aims to provide near real-time feedback, replacing slower HPLC workflows and enabling consistent reaction control.

Methodology

Samples of milled cannabis flower and extracted oils were subjected to controlled heating (75–150 °C, 25–90 min) to induce decarboxylation. Flower samples were extracted with pentane and sonicated; oil samples were applied directly to the ATR crystal. Spectra were acquired every 5 min using FTIR, and reference concentrations were determined by HPLC analysis for model calibration.

Instrumentation

• Agilent Cary 630 FTIR spectrometer with ZnSe optics and diamond ATR module
• Agilent MicroLab software with built-in decarboxylation workflow
• Agilent 1220 Infinity II LC System for HPLC reference measurements
• Standard laboratory hot plate, round-bottom flask, and sonication bath for sample preparation

Key Results and Discussion

A PCA-based prediction model correlated FTIR spectra with HPLC data, expressing reaction progress as percent decarboxylation. Correlation coefficients (R2) were 0.961 for THCA→THC in oil, 0.987 for CBDA→CBD in oil, and 0.953 for THCA→THC in flower. The model accurately tracked late-stage decarboxylation, enabling precise endpoint determination within 5- to 10-minute windows.

Benefits and Practical Applications

• Rapid, non-destructive monitoring on the production floor
• Minimal sample preparation and reagent use
• Immediate, color-coded results within minutes
• Reduced reliance on off-site HPLC testing and faster decision-making

Future Trends and Potential Applications

Integration of FTIR process control with automated reactor systems could enable closed-loop temperature and time adjustments. Expanding spectral models to include secondary cannabinoids and terpene stability offers potential for comprehensive quality monitoring in cannabis and hemp industries.

Conclusion

The combination of the Agilent Cary 630 FTIR spectrometer and the DELIC Labs decarboxylation model provides a fast, easy, and reliable solution for monitoring cannabinoid conversion. This approach improves product consistency, reduces processing costs, and supports real-time decision-making, representing a significant advance in cannabis post-processing control.