A novel comprehensive strategy for residual pesticide analysis in cannabis flower

Significance of the topic

Cannabis flower tests for residual pesticides are critical for consumer safety and regulatory compliance. As more U.S. states authorize recreational or medical cannabis use, reliable multi-residue analysis methods are essential to detect low-level contaminants in complex plant matrices.

Objectives and study overview

This work outlines a unified workflow to screen and quantify up to 214 pesticide compounds in cannabis flower. The approach employs a single acetonitrile extraction and solid-phase cleanup, with combined analysis by GC/MS/MS and LC/MS/MS to meet diverse state regulations and action limits.

Methodology and instrumentation

The sample preparation begins with a 1 g homogenized flower extracted in 15 mL of pesticide-grade acetonitrile, followed by gravity SPE cleanup and dilution.

• GC/MS/MS system: Agilent 7010 tandem quadrupole with High Efficiency Source, dual non-polar and mid-polar columns, midcolumn backflush
• LC/MS/MS system: Agilent 6470 tandem quadrupole coupled to Agilent 1260 Infinity HPLC, InfinityLab Poroshell 120 Phenyl-Hexyl column, online multisampler pretreatment

Main results and discussion

Using large dilution factors (250–500×) and dispersive SPE cleanups, matrix interferences were drastically reduced. For GC/MS/MS, 94 % of targets achieved an LOQ of 0.1 mg/kg; LC/MS/MS reached 0.1 mg/kg for 89 % of the compounds. Recoveries for 212 out of 214 analytes fell between 70 % and 120 % with relative standard deviations below 12 %. High-throughput calibration curves exhibited R² values above 0.99 for both platforms.

Benefits and practical applications

• Simplified extraction without QuEChERS hydration or pH adjustments
• Single-extract workflow supports both GC and LC analyses
• High sensitivity instruments allow large dilution to control matrix effects
• Improved instrument uptime and lower maintenance demands

Future trends and possibilities of use

Advances in ultrahigh-resolution MS and automation will further streamline multi-residue testing in cannabis and other botanicals. Integration of data-driven calibration and real-time matrix-effect correction could enhance throughput and reliability. Emerging technologies like ambient ionization may offer rapid screening options.

Conclusion

The described comprehensive method provides accurate, reproducible pesticide residue analysis in cannabis flower. By leveraging high-sensitivity tandem quadrupole systems and optimized sample preparation, laboratories can meet stringent regulatory criteria with minimal instrument downtime.

References

• Hengel, M. J. Expanded Method Development for the Determination of Pesticides in Dried Hops by Liquid Chromatography with Tandem Mass Spectrometry. J. Am. Soc. Brewing Chemists 2011, 69(3), 121–126.