In the United States, Canada, and other regions where medicinal or adult recreational cannabis use has been legalized, regulatory agencies require chemical and biological testing of the products to ensure compliance and safety. The global movement for cannabis legalization drives the demand for cannabis analytical testing methods, including potency determination, trace metals analysis, residual solvents, and terpenes analysis, microbial screening, and quantitation of micotoxins. Of these assays, residual pesticide analysis is particularly challenging due to the very low LOQs required by regulatory entities.

By the beginning of 2020, the list of pesticides regulated by U.S. state legislation and by Health Canada comprised approximately 100 pesticides, with California currently having the largest target list of pesticides tested in recreational cannabis in the U.S.1 Meanwhile, the Canadian target list mandated by Health Canada generally exhibits lower required LOQs than any U.S. state.2 Of all the pesticides currently regulated in the cannabis industry in North America, at least 27 compounds and their isomers present a challenge for electrospray TQ LC/MS.

A well-defined sample preparation procedure3 and state-of-the-art GC4-6 and LC7-10 triple quadrupole mass spectrometry are required to enable success in meeting diverse regulatory requirements. This application note focuses on gas chromatography‑triple quadrupole mass spectrometry (TQ GC/MS) analysis of 27 GC‑amenable pesticides regulated in cannabis in California by the Bureau of Cannabis Control (BCC) and in Canada by Health Canada that commonly stand out as challenging to analyze using electrospray TQ LC/MS. The California and Canadian required limits of quantitation (LOQs) were successfully met for the 27 pesticides. Excellent quantitative accuracy was achieved at action levels established in both California and Canada.

The rest of the pesticides regulated in California and Canada are analyzed at the action level by TQ LC/MS as reported in application notes 5994‑1743EN,7 5994‑0648EN,8 and 5994-0429EN.9

Materials and methods

An Agilent 8890/7010B TQ GC/MS system (Figure 1A) configured to achieve the highest sensitivity and minimize common pitfalls with pesticide analyses in high‑matrix cannabis samples was used. The GC was configured with the 7693 autosampler and 150-position tray, a MultiMode inlet (MMI) operated in cold solvent vent mode. Mid-column backflush was employed using the Agilent Purged Ultimate Union (PUU) installed between two identical 15 m columns. The 8890 pneumatic switching device (PSD) (Figure 1B) supplied helium to the backflush system. The triple quadrupole mass spectrometer was equipped with the High Efficiency Source (HES) operated in electron ionization (EI) mode at 300 °C. Data were acquired in dynamic MRM (dMRM) mode. dMRM optimizes dwell time distributions to accurately identify and quantify large multi-analyte assays. The acquisition method was retention time-locked to match retention times in the Agilent MassHunter Pesticide & Environmental Pollutant MRM Database (P&EP 4) that allowed for seamless development of the acquisition method. The instrument operating parameters are listed in Table 1. Agilent MassHunter Workstation revision 10, including MassHunter Acquisition 10 SR1, MassHunter Qualitative 10, and MassHunter Quantitative 10.1 packages were used in this work.

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