Analysis of the California list of Pesticides and Mycotoxins in Edibles

Significance of the Topic

As cannabis legalization expands, regulatory frameworks require reliable screening of pesticide and mycotoxin residues in edible products. Ensuring consumer safety demands analytical methods with high sensitivity and broad coverage to detect compounds at low action levels in complex matrices such as brownies.

Goals and Overview of the Study

This work presents a unified sample preparation and dual-instrument workflow for simultaneous quantitation of the California-regulated list of pesticides and mycotoxins in cannabis brownies. The strategy integrates liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS) to cover a wide range of analyte chemistries.

Methodology and Instrumentation

• Sample Preparation
  • Weigh 0.5 g of homogenized brownie.
  • Extract with 1.5 mL of acetonitrile containing 1 % acetic acid.
  • Vortex 30 s and sonicate 5 min.
  • Pass supernatant through 100 mg C18 SPE cartridge.
  • Split eluate: 750 µL for LC-MS/MS (diluted with water) and the remainder through dSPE (MgSO₄ + PSA) for GC-MS/MS.
• LC-MS/MS Conditions
  • Column: Raptor ARC-18, 2.7 µm, 100 × 2.1 mm with guard.
  • Mobile phases: water/2 mm ammonium formate/0.1 % formic acid and methanol with the same modifiers.
  • Gradient: 5 % B to 100 % B in 10.5 min.
  • Instrument: Shimadzu LCMS-8060, ESI source, column at 40 °C, autosampler at 10 °C, 2 µL injection.
• GC-MS/MS Conditions
  • Column: Rxi-5ms, 30 m × 0.25 mm, 0.25 µm film.
  • Injection: splitless, 250 °C inlet, 0.5 min splitless, 1 mL/min purge.
  • Oven: 90 °C (1 min) to 310 °C at 25 °C/min, hold 10 min.
  • Carrier gas: helium, 1.4 mL/min constant flow.
  • Instrument: Thermo Trace 1310–TSQ 8000, EI source at 330 °C, transfer line at 290 °C.

Main Results and Discussion

The validated workflow achieved limits of quantitation at or below 100 ng/g for all target compounds, meeting California action levels. Linearity coefficients (R²) exceeded 0.994 for pesticides and mycotoxins. Accuracy ranged from 93 % to 112 %, and precision (RSD) remained below 12 % across three tested levels (10, 100 and 500 ng/g). The procedure reduced solvent consumption to 3.5 mL per sample, enhancing sustainability.

Benefits and Practical Applications

• Comprehensive multi-residue capability for over 100 pesticides and mycotoxins.
• High sensitivity and robustness suitable for regulatory compliance.
• Reduced solvent usage lowers cost and environmental impact.
• Streamlined workflow allows high-throughput analysis in quality control laboratories.

Future Trends and Possibilities

• Integration of automation for sample preparation to boost throughput.
• Expansion to include emerging contaminants and polar metabolites.
• Implementation of high-resolution mass spectrometry for untargeted screening.
• Adoption of microextraction techniques to further minimize solvent usage.

Conclusion

The combined SPE/dSPE cleanup with LC-MS/MS and GC-MS/MS analysis provides a robust, sensitive, and efficient approach to monitor California-regulated pesticides and mycotoxins in edible cannabis products. This methodology supports regulatory compliance and promotes consumer safety.

Used Instrumentation

• Shimadzu LCMS-8060 (LC-MS/MS)
• Thermo Trace 1310 coupled to TSQ 8000 (GC-MS/MS)

References

1. Reyes-Garcés N, Myers C. Analysis of pesticides and mycotoxins in cannabis brownies. Restek Technical Article FFAN3149-UNV.