Residual Solvents Testing in Cannabis using Zebron™ ZB-624PLUS™ GC Column

Importance of the topic

Cannabis extracts and concentrates often retain residual solvents from processing. Accurate quantification of these residues is critical for consumer safety, regulatory compliance and consistent product quality.

Objectives and Study Overview

This study aimed to develop and demonstrate a reliable GC-FID method for screening and quantifying common residual solvents in cannabis matrices. A Zebron™ ZB-624PLUS™ column was evaluated for its ability to resolve both polar and nonpolar solvent targets.

Methodology and Instrumentation

• Column: Zebron ZB-624PLUS, 30 m × 0.25 mm × 1.40 µm (Part No. 7HG-G040-27).
• Injection: Split ratio 10:1, injection temperature 200 °C, injection volume 1 µL.
• Carrier gas: Helium at 1.0 mL/min (constant flow).
• Oven program: 35 °C (4 min) → 50 °C @ 20 °C/min (1 min) → 160 °C @ 10 °C/min (4 min) → 300 °C @ 15 °C/min (5 min).
• Detector: Flame ionization detector at 240 °C.
• Inlet liner: Zebron PLUS Straight Z-Liner™ (AG2-0A03-05) for compatibility with Agilent® and Thermo Scientific® systems.

Key Results and Discussion

The method achieved baseline separation of low-boiling solvents (propane, 2-methylpropane, n-butane, neopentane, ethylene oxide) as well as a 17-compound panel including alcohols, ketones, chlorinated solvents and aromatic hydrocarbons. Peak shapes were symmetrical and retention times were reproducible. The ZB-624PLUS phase demonstrated excellent selectivity for both polar and nonpolar compounds and maintained a stable baseline at temperatures up to 320 °C.

Benefits and Practical Applications

• Ensures precise quantification of hazardous residual solvents to meet health and safety regulations.
• High thermal stability extends column lifetime and supports rapid temperature ramps.
• Enhanced selectivity improves resolution of critical pairs such as m-, o- and p-xylenes.

Future Trends and Applications

Emerging workflows may integrate this GC-FID approach with mass spectrometric detection for increased sensitivity and specificity. Method adaptation to other botanicals and food matrices, as well as automated sampling platforms, will further streamline quality control. Advances in inert ceramic liners and low-bleed stationary phases may enhance detection limits and robustness.

Conclusion

The Zebron ZB-624PLUS GC-FID method provides a robust, reproducible and selective solution for residual solvent analysis in cannabis products, supporting laboratory throughput and regulatory compliance.

Reference

• Dhandapani R., Aqeel Z., Misa A. Residual Solvents Testing in Cannabis using Zebron™ ZB-624PLUS™ GC Column. Phenomenex Application Note TN60250418_W, 2018.