Analysis of the California list of Pesticides and Mycotoxins in Edibles

Importance of the Topic

The legalization of cannabis for both medical and recreational use has heightened concerns over pesticide and mycotoxin residues in edible products. Effective analytical strategies are critical to safeguard consumer health and meet California’s stringent regulatory standards.

Objectives and Study Overview

This work describes the development of a unified analytical workflow for simultaneous quantitation of the California-regulated list of pesticides and mycotoxins in cannabis-infused brownies. The approach leverages both LC-MS/MS and GC-MS/MS to cover a broad spectrum of chemical properties and achieve low detection limits.

Methodology and Instrumentation

The protocol integrates a straightforward extraction with dual-platform analysis:

• Sample Preparation Steps:
  
  • Weigh 0.5 g of homogenized brownie and spike with target standards and internal standards.
  • Add 1.5 mL of 1% acetic acid in acetonitrile, vortex for 30 seconds, and sonicate for 5 minutes.
  • Pass the extract through a 100 mg C18 SPE cartridge; collect the eluate.
  • For LC-MS/MS analysis, dilute 750 µL of extract with 250 µL of water and inject directly.
  • For GC-MS/MS analysis, perform dSPE cleanup using magnesium sulfate and PSA, then dilute 500 µL of extract with 500 µL of 1% acetic acid in acetonitrile before injection.
• Instrumentation:
  
  • LC-MS/MS: Shimadzu LCMS-8060 with Raptor ARC-18 column (100 × 2.1 mm, 2.7 µm), electrospray ionization, gradient elution using water and methanol containing 2 mM ammonium formate and 0.1% formic acid.
  • GC-MS/MS: Thermo Trace 1310 coupled to TSQ 8000, Rxi-5ms column (30 m × 0.25 mm × 0.25 µm), splitless injection, helium carrier gas, electron ionization source.

Main Results and Discussion

The workflow achieved limits of quantitation at or below 100 ng/g for all target pesticides and mycotoxins. Calibration curves displayed excellent linearity (R² > 0.99), accuracy ranged from 96% to 107%, and precision (RSD) remained under 12% at spiking levels of 10, 100, and 500 ng/g. Notably, solvent consumption was minimized to approximately 3.5 mL per sample.

Benefits and Practical Applications

This streamlined protocol offers:

• Reduced solvent use and waste generation.
• Compatibility with routine QA/QC laboratories via simple SPE and dSPE cleanup.
• Comprehensive coverage of a diverse set of pesticides and mycotoxins specified by California regulations.

Future Trends and Applications

Potential developments include the integration of high-resolution mass spectrometry for non-target screening, automation or miniaturization of sample preparation to boost throughput, and extension of the method to other cannabis matrices such as oils and tinctures.

Conclusion

The combined LC-MS/MS and GC-MS/MS approach provides a sensitive, accurate, and efficient solution for monitoring pesticide and mycotoxin residues in cannabis edibles, meeting California regulatory requirements while minimizing resource consumption.

References

Reyes-Garcés N., Myers C. Analysis of pesticides and mycotoxins in cannabis brownies. Restek Corporation Technical Article.