Simple and Accurate Quantification of THC and CBD in Cannabis-Infused Chocolate Edibles using Agilent Captiva EMR—Lipid Removal and the Agilent 1260 Infinity II LC System

Importance of the Topic

Accurate quantification of Δ9-THC and CBD in high-fat edibles such as chocolate is essential for regulatory compliance, consumer safety, product labeling, and forensic applications. The complex matrix of chocolate—rich in fats, sugars, proteins, and flavonoids—poses significant challenges to conventional sample preparation and LC/UV analysis, leading to column fouling, poor sensitivity, and inaccurate results.

Objectives and Study Overview

• Develop a streamlined, cost-effective workflow to grind and homogenize chocolate edibles.
• Optimize extraction and cleanup to remove lipids and matrix interferences while retaining cannabinoids.
• Demonstrate method performance—linearity, accuracy, precision, and robustness—using Agilent Captiva EMR-Lipid and an Agilent 1260 Infinity II LC system.

Methodology

• Sample Preparation: Chocolate bars were finely chopped, frozen at –20 °C, and homogenized with ceramic beads.
• Extraction: 2% formic acid in cold acetonitrile was added to precipitate proteins and begin lipid separation.
• Cleanup: Gravity-flow or positive-pressure filtration through Captiva EMR-Lipid cartridges removed nearly 100% of fats without capturing cannabinoids.
• Calibration: Matrix-matched curves prepared by serial dilution in non-infused chocolate extract over 0.5–100 µg/mL for each analyte.

Instrumental Setup

• HPLC: Agilent 1260 Infinity II LC with Poroshell 120 EC-C18 column, mobile phases 0.1% formic acid in water and 0.05% formic acid in methanol, UV detection at 230 nm.
• MS Cleanliness Assessment: Agilent 6545 LC/Q-TOF using Jet Stream ESI for TIC comparisons.
• Consumables: Agilent Captiva EMR-Lipid 3 mL cartridges, certified THC/CBD standards, ultrapure solvents.

Main Results and Discussion

• Solvent Choice: Acidified acetonitrile yielded cleaner extracts and lower TIC background than methanol.
• Cleanup Comparison: EMR-Lipid and winterization both reduced residue to ~0.4 mg versus 26–30 mg for untreated or QuEChERS-treated samples.
• UV Signal: THC peak area was significantly higher after EMR-Lipid cleanup compared to other methods, enhancing sensitivity.
• Linearity: Calibration curves from 0.5 to 100 µg/mL showed R² >0.9996 for both cannabinoids.
• Accuracy and Precision: Intra- and inter-day recoveries 96–117% with RSDs <7%; matrix effects <5%.
• Stability: Calibrators stable for seven days in the autosampler at 20 °C.

Benefits and Practical Applications

• Rapid sample throughput with minimal equipment cleaning between runs.
• Reduced solvent consumption and HPLC maintenance downtime.
• Reliable potency testing for regulatory, QA/QC, and forensic laboratories.

Future Trends and Potential Applications

• Integration with automated homogenizers and positive-pressure manifolds to further increase throughput.
• Use of certified reference materials for a broader range of cannabinoids.
• Extension of the EMR-Lipid cleanup strategy to other fatty food matrices and coupling with MS/MS quantitation.

Conclusion

The combination of acidified acetonitrile extraction and Agilent Captiva EMR-Lipid cleanup delivers a robust, accurate, and efficient protocol for quantifying THC and CBD in chocolate edibles. This method improves laboratory productivity, reduces instrument maintenance, and meets the stringent requirements of modern cannabis testing.

References

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