Optimizing Sample Preparation in Pesticides Analysis for Cannabis

Importance of the Topic

Reliable detection and quantitation of pesticide residues in cannabis are essential for consumer safety and regulatory compliance. Cannabis plant material presents a challenging matrix due to high levels of terpenes, cannabinoids, flavonoids and other endogenous compounds that can interfere with trace analysis and instrument performance.

Study Objectives and Overview

This work evaluates a standardized sample preparation workflow aligned with a multiplatform Agilent instrumentation approach. The goal is to achieve robust, high-throughput analysis of both LC/MS/MS-amenable and GC/MS/MS-amenable pesticides and mycotoxins in dried cannabis flower, meeting current state-mandated action limits and anticipating future requirements.

Used Instrumentation

• Agilent 1290 Infinity II LC coupled to Agilent 6470 or Ultivo triple quadrupole LC/MS with Jet Stream ESI source
• Agilent 8890 GC system coupled to Agilent 7010B triple quadrupole GC/MS

Applied Methodology

Sample homogenization: 1 g dried cannabis flower is weighed and mixed with ceramic beads, then shaken at high speed until finely powdered. Extraction: add 15 mL pesticide-grade acetonitrile, vortex or Geno/Grinder shake for 3–5 minutes. Clean-up: gravity-flow SPE using SampliQ C18 cartridges, followed by rinses with additional acetonitrile. Dilution: final volume adjusted to 25 mL (25-fold dilution). For LC/MS/MS, a 250-fold injection dilution (50 µL extract + 450 µL water/methanol with 0.1% formic acid) is performed. For GC/MS/MS, a 125-fold injection dilution (200 µL extract + 800 µL hexane/acetone with 0.1% formic acid) is used.

Main Results and Discussion

The workflow delivered limits of detection between 0.5 and 50 ppb for LC-amenable pesticides and mycotoxins, with malathion at 100 ppb. Forty-three GC-amenable pesticides achieved in-vial LOQs ≤ 0.8 ppb (≤ 100 ppb in plant), satisfying California Bureau of Cannabis Control requirements. Sequential injection chromatograms showed stable retention, low carryover and RSDs generally below 12% at LOQ levels.

Benefits and Practical Applications

• Rapid return on investment via a harmonized sample prep protocol across LC and GC platforms
• Enhanced throughput with minimized maintenance and solvent consumption
• Flexibility to adapt to evolving regulatory lists and lower action limits

Future Trends and Opportunities

Regulations are expected to expand analyte lists and tighten detection limits, driving demand for even more sensitive workflows. Automation of sample preparation, integration of high-resolution mass spectrometry and advanced data analytics will further improve throughput, data quality and laboratory efficiency.

Conclusion

The standardized sample preparation combined with Agilent’s LC/MS/MS and GC/MS/MS systems provides a robust, future-proof solution for comprehensive pesticide and mycotoxin testing in cannabis, ensuring compliance with current and forthcoming regulatory requirements.

References

• Roy J-F, Andrianova A, Westland J, Churley M. A Sensitive and Robust Workflow to Measure Residual Pesticides and Mycotoxins from the Canadian Target List in Dry Cannabis Flower. Agilent Technologies Application Note 5994-0429EN, 2018.
• Andrianova A, Westland J, Churley M. Sensitive and Robust Detection of Pesticides Regulated in California in Dried Cannabis Plant Material. Agilent Technologies Application Note 5994-0568EN, 2019.
• Stone PJW, Westland J, Andrianova A. Determination of Pesticides and Mycotoxins as Defined by California State Recreational Cannabis Regulations – A Combined LC/MS/MS Analysis Method. Agilent Technologies Application Note 5994-0648EN, 2019.