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

Ensuring that cannabis products meet stringent safety standards requires reliable detection of trace pesticide residues. Health Canada mandates testing for a defined list of 96 pesticide active ingredients at levels as low as 20 ppb in dried cannabis. A robust multi‐residue analytical workflow is essential to protect consumer health, comply with regulations, and support licensed producers in quality control.

Objectives and Study Overview

This application note describes the development and validation of a streamlined sample preparation and dual chromatographic approach—ultra‐performance liquid chromatography tandem mass spectrometry (UPLC‐MS/MS) and atmospheric pressure gas chromatography tandem mass spectrometry (APGC‐MS/MS)—to quantify 96 pesticides in cannabis. The goal was to achieve sensitivity, reproducibility, and regulatory compliance using a single quadrupole‐based mass spectrometer with interchangeable ion sources.

Methodology and Instrumentation

Sample Preparation

• Freeze cannabis in liquid nitrogen, grind, and remove stems/seeds.
• Extract 0.5 g of ground material with 5 mL acetonitrile (vortex 5 min, centrifuge 5 min at 5 000 rpm).
• Clean up 1 mL supernatant using QuEChERS dispersive SPE (MgSO₄, PSA, C18, GCB).

Chromatography and Detection

• UPLC‐MS/MS: Waters ACQUITY UPLC H-Class PLUS with BEH C18 column (2.1 × 100 mm, 1.7 µm); gradient of methanol, water, 0.1% formic acid; Xevo TQ-S micro with ESI+; 84 pesticides monitored by MRM.
• APGC‐MS/MS: Agilent 7890B GC with DB-5 MS column (30 m × 0.25 mm × 0.25 µm); helium carrier, pulsed splitless injection; APGC+ interface on the same Xevo TQ-S micro; 12 pesticides by MRM.

Main Results and Discussion

Linearity and Sensitivity

• Matrix-matched calibration curves showed r² > 0.99 over broad concentration ranges for all compounds.
• Limits of quantitation (LOQs) met or surpassed Health Canada criteria (down to 20 ppb for most analytes).

Accuracy and Precision

• Spike recoveries at LOQs ranged from 81.7% to 117.6% (Health Canada acceptance: 70–120%).
• Relative standard deviations were <20% for all analytes, demonstrating reproducible performance.

Benefits and Practical Applications

This method delivers a unified workflow for both liquid and gas chromatography on a single MS platform, reducing instrument footprint and simplifying laboratory operations. Minimal sample preparation and fast chromatographic runs support high throughput. The robust method can be readily adopted by testing laboratories to ensure compliance with current cannabis pesticide regulations.

Future Trends and Potential Applications

As regulatory lists evolve and grow, the universal source architecture of the Xevo TQ-S micro allows rapid method adaptation to include new analytes. Integration of high-resolution mass spectrometry or automated sample cleanup could further enhance sensitivity and selectivity. Expanding this approach to other complex botanical or food matrices may streamline multi‐residue pesticide analysis across industries.

Conclusion

The described multi-residue method combining UPLC-MS/MS and APGC-MS/MS provides sensitive, accurate, and reproducible quantification of 96 pesticides in cannabis. It fully satisfies Canadian regulatory requirements while offering operational flexibility and efficiency for routine testing laboratories.

References

1. Moulins JR, Blais M, Montson K et al. Multiresidue Method of Analysis of Pesticides in Medical Cannabis. J AOAC Int. 2018;110(6):1948–1960.
2. Health Canada. Mandatory Cannabis Testing for Pesticide Active Ingredients. 2018. Available at canada.ca/phac-aspc/products-services/drugs-health-products/cannabis/testing-pesticide-requirements.
3. Kovalczuk T, Jech M, Poustka J, Hajslova J. UPLC–MS/MS: A Novel Challenge in Multiresidue Pesticide Analysis in Food. Anal Chim Acta. 2006;577:xx–xx.