Routine Analysis of Cannabis for Pesticides and Mycotoxins using UPLC-MS/MS and GC-MS/MS

Importance of the topic

The rapid expansion of medical and recreational cannabis cultivation has heightened the demand for comprehensive safety and quality control testing. Pesticide residues and mycotoxins pose significant health risks, and reliable multi-residue screening is essential to ensure consumer safety and regulatory compliance.

Objectives and study overview

This study aimed to establish a streamlined workflow for simultaneous detection of hundreds of pesticides and key mycotoxins in cannabis flower, using both UPLC-MS/MS and GC-MS/MS. The method was designed to meet stringent California action levels and to deliver high throughput, sensitivity, and selectivity.

Methodology and instrumentation

Sample preparation and cleanup:

• Weighed 0.5 g of ground cannabis into a centrifuge tube and added 5 mL acetonitrile.
• Shook in a Geno Grinder (5 min at 1500 rpm), then transferred 1 mL extract to a dSPE tube.
• Mixed for 1 min, centrifuged, and transferred supernatant to vials for analysis.

UPLC-MS/MS details:

• Instrument: Waters ACQUITY H-Class with Xevo TQ-S micro.
• Column: XBridge C18 (2.1 × 150 mm, 2.5 µm) at 50 °C.
• Mobile phases: A = water + 5 mM ammonium formate + 0.02% formic acid; B = methanol.
• Flow: 0.40 mL/min; injection: 5 µL; gradient from 2% to 99% B over 15 min.

GC-MS/MS details:

• Instrument: Xevo TQ-GC with helium carrier gas.
• Column: Rxi-5MS (20 m × 0.18 mm, 0.18 µm).
• Oven program: 60 °C hold 0.45 min, ramp to 330 °C at 18.7 °C/min, hold 2.25 min.
• Injection: 1 µL splitless; MRM for target pesticides.

Key results and discussion

• Recoveries for most pesticides and mycotoxins ranged between 80% and 120%.
• dSPE cleanup markedly reduced matrix suppression, improving data precision.
• Pesticide linearity was demonstrated from 0.025 to 0.50 µg/g (R² > 0.990); GC-MS/MS provided confirmatory data for poorly ionizing compounds.
• Mycotoxins (aflatoxins B1, B2, G1, G2, ochratoxin A) showed linear response from 0.005 to 0.10 µg/g (R² > 0.990).
• Representative MRM chromatograms confirmed clear separation and sensitivity at low ppb levels.

Benefits and practical applications

This unified workflow offers high throughput screening with minimal sample prep time, robust performance across diverse cannabis matrices, and the ability to meet state regulatory limits. Automated method setup via a spectral library database reduces method development time and error risk.

Future trends and potential applications

Advances may include expansion of target analyte lists, integration of high-resolution mass spectrometry for non-target screening, further miniaturization of workflows, enhanced automation, and data-driven optimization. Adoption of real-time monitoring and cloud-based data analysis will support broader quality assurance in cannabis production.

Conclusion

The combined UPLC-MS/MS and GC-MS/MS protocol with simple extraction and dSPE cleanup delivers a rapid, sensitive, and reliable solution for multi-residue pesticide and mycotoxin analysis in cannabis. This approach fulfills regulatory requirements while ensuring high data quality and laboratory efficiency.

References

1. Tran K, Organtini K, Twohig M, Alden P, Young MS, Meruva N, Rosnack K, Fujimoto G, Stevens R, Roush J, Hudalla CJ. Analysis of residual pesticides and mycotoxins in cannabis using UPLC-MS/MS and GC-MS/MS to meet California regulatory requirements. Waters Application Note 720006465EN. 2018.