A Multi-Residue Method for the Analysis of Pesticides in Cannabis Using UPLC-MS/MS and APGC-MS/MS to Meet Canadian Regulatory Requirements

Importance of the topic

Routine testing of pesticide residues in cannabis is critical to ensure consumer safety and comply with Canadian regulations, which mandate limits as low as 20 ppb for dried products. A robust multi‐residue approach combining both liquid and gas chromatographic techniques meets the demand for sensitive, reproducible screening across a broad range of analytes.

Study objectives and overview

This work presents a streamlined workflow for the simultaneous multi‐residue analysis of 96 regulated pesticides in cannabis. By using a single extraction and cleanup protocol followed by analysis on one tandem quadrupole mass spectrometer equipped for both UPLC‐MS/MS and atmospheric pressure GC‐MS/MS (APGC‐MS/MS), the method aims to satisfy Health Canada’s action levels with minimal sample preparation and rapid run times.

Methodology and Instrumentation

Sample Preparation and Cleanup:

• Grind 0.5 g frozen cannabis, extract with 5 mL acetonitrile, centrifuge and transfer 1 mL supernatant to a d‐SPE cartridge (MgSO4, PSA, C18, GCB).
• Shake 1 min, centrifuge 5 min and directly vial extracts for analysis.

Calibration:

• Matrix‐matched curves from 1–6400 ppb ensure accurate quantitation across analytes with varying ionization efficiencies.

Instrumentation:

• UPLC‐MS/MS: Waters ACQUITY UPLC H-Class PLUS, BEH C18 column, Xevo TQ-S micro with ESI+ for 84 pesticides.
• GC‐MS/MS: Agilent 7890B, DB-5 MS column, Xevo TQ-S micro with APGC+ for 12 thermally stable pesticides.
• MassLynx v4.2 software controlled both analyses.

Main results and discussion

Method Validation:

• Average recoveries for all 96 analytes ranged between 81.7 % and 117.6 % (acceptable 70–120 %), with RSDs below 20 %.
• Limits of quantification (LOQs) met or exceeded Health Canada requirements (20–1000 ppb depending on compound).
• Linearity (r²>0.99) achieved across tested calibration ranges.

Representative Chromatograms and Calibration:

• UPLC‐MS/MS examples for acetamiprid, cyprodinil, fenoxycarb, and tetrachlorvinphos showed clear separation and sensitive detection at 25–50 ppb.
• GC‐MS/MS examples for endosulfan α and fenvalerate confirmed performance at 100–400 ppb.

Benefits and practical applications of the method

By leveraging a universal source tandem quadrupole instrument, laboratories gain:

• Efficient throughput via one extraction and one instrument for both LC and GC analyses.
• High sensitivity to detect regulated pesticides at legislated action levels.
• Flexibility to adapt to evolving regulatory lists or emerging contaminants.

Future trends and possibilities

Anticipated developments include further expansion of regulated pesticide lists, integration of high-resolution MS for non‐target screening, and automation of sample preparation. Combining data from LC‐MS/MS and APGC‐MS/MS will support comprehensive contaminant surveillance in cannabis and other complex botanical matrices.

Conclusion

The described multi‐residue workflow meets Canadian regulatory requirements, delivering sensitive, reproducible analysis of 96 pesticides in cannabis. The dual‐mode tandem quadrupole approach streamlines testing, enhances laboratory efficiency, and provides a scalable platform for future analytical challenges.

References

1. Moulins J. R. et al. Multiresidue Method of Analysis of Pesticides in Medical Cannabis. J. AOAC Int. 2018, 101(6), 1948–1960.
2. Health Canada. Mandatory Cannabis Testing for Pesticide Active Ingredients. 2018.
3. Kovalczuk T. et al. UPLC-MS/MS: A Novel Challenge in Multiresidue Pesticide Analysis in Food. Anal. Chim. Acta 2006, 577.
4. Tienstra M. et al. Fast Gas Chromatographic Residue Analysis in Animal Feed Using APGC-MS/MS. J. Chromatogr. A 2015, 1422.
5. Cherta L. et al. Application of APGC-MS for Multiclass Pesticides in Fruits and Vegetables. J. Agric. Food Chem. 2013, 61, 2735–2745.