Determination of Pesticides and Mycotoxins as Defined by California State Recreational Cannabis Regulations

Importance of the topic

Ensuring the safety and quality of recreational cannabis products is a growing public health priority. State regulations, particularly in California, mandate strict limits on pesticide residues and mycotoxin contamination in cannabis flower. Robust analytical methods are essential to verify compliance, protect consumers, and support the emerging cannabis testing industry.

Objectives and overview of the article

This application note presents a combined LC/MS/MS workflow developed by Agilent Technologies for simultaneous determination of the full California action list of pesticides and mycotoxins in cannabis flower. The goals include demonstrating sample preparation, chromatographic separation, mass spectrometric detection, and data review techniques that meet or exceed regulatory limits.

Methodology and instrumentation

Sample preparation employs:

• Fine grinding of 1 g cannabis flower with ceramic homogenizers.
• Extraction with 15 mL acetonitrile and mechanical shaking, followed by dilution and cleanup using SampliQ C18 SPE cartridges.
• Final 1:250 dilution in 25/75 water/methanol with 0.1 % formic acid.
• Injector sandwich program (water–sample–water) to maintain peak shape on reversed-phase UHPLC.

Chromatography and detection use:

• Agilent 1290 Infinity binary pump, 1260 Infinity II autosampler, and multicolumn thermostat.
• Agilent Poroshell 120 Phenyl-Hexyl column, 0.5 mL/min gradient (30 % to 100 % methanol with 0.1 % formic acid).
• Agilent 6470 or Ultivo triple quadrupole MS with Jet Stream ESI in positive and negative modes.
• MRM transitions optimized via MassHunter Optimizer; overlapped injections for high throughput.

Key results and discussion

• Calibration curves for representative analytes showed linearity (R2 ≥ 0.990) over regulatory ranges.
• Limits of quantification (LLOQs) typically 0.1–2.5 ppb in extract (equivalent to 25–625 ppb in raw flower), below California action levels.
• Recovery studies yielded 88 %–130 % for pesticides and 100 %–105 % for mycotoxins at relevant spike levels.
• Chromatographic peak shapes remained sharp and symmetric despite high organic content, thanks to injector pretreatment.

Benefits and practical applications

• Single method covers over 90 pesticides and mycotoxins, reducing sample processing time.
• 11-minute run time with overlapped injections supports high-throughput testing.
• MassHunter Quantitative Analysis software provides review-by-exception, two user-role GUIs (Scientist and Analyst), and custom reporting templates aligned with regional regulations.
• Compatible with additional GC/MS/MS methods for analytes lacking LC amenability.

Future trends and potential applications

• Integration of high-resolution MS for non-targeted screening and confirmatory analysis.
• Automation of sample preparation (robotics, on-line SPE) to further increase throughput and reproducibility.
• Expansion to other state and international regulatory lists, including emerging contaminants.
• Data analytics improvements using machine learning for pattern recognition and outlier detection.

Conclusion

The described Agilent LC/MS/MS workflow delivers a validated, efficient, and sensitive approach for simultaneous pesticide and mycotoxin testing in cannabis flower, fully meeting California regulatory requirements. High recoveries, low LLOQs, and streamlined data review make it well suited for routine quality control laboratories.

References

• Bureau of Marijuana Control. Proposed Text of Regulations, California Code of Regulations Title 16 Division 42, Chapter 5. Testing Laboratories.
• Mordehai A., Fjeldsted J. Agilent Jet Stream Thermal Gradient Focusing Technology. Agilent Technologies Technical Overview, publication 5990-3494EN, 2009.
• Andrianova A.A. et al. Sensitive and Robust Detection of Pesticides in Dried Cannabis Plant Material Regulated in California. Agilent Technologies Application Note 5994-0568EN, 2019.