Agilent Sample Preparation The Pesticide Analysis Workflow

Significance of the Topic

Cannabis testing for pesticide residues presents unique challenges due to the plant’s complex biochemical composition, lack of established federal tolerances, and the rapid growth of legal cannabis markets. Reliable sample preparation is essential to ensure accurate, sensitive pesticide quantitation, protect consumer safety, and maintain regulatory compliance.

Objectives and Study Overview

This study aimed to compare and optimize multiple sample preparation approaches for pesticide analysis in cannabis flower, edibles, and high-fat products. Key goals included:

• Assessing traditional extraction techniques (QuEChERS, SPE) and novel dispersive SPE (dSPE) cleanups.
• Evaluating the impact of custom sorbent combinations and dilution strategies on matrix removal and analyte recovery.
• Demonstrating the performance of a new EMR-Lipid dispersive sorbent for high-fat matrices.

Methodology and Instrumentation

Sample preparation workflows employed:

• ACN (1% acetic acid) or MeOH extraction of 1.5 g ground cannabis or edible sample.
• QuEChERS AOAC salt partitioning (acetate, citrate, NaCl, MgSO₄) vs. direct ACN extraction.
• Cleanup using:
  
  • Universal dSPE (PSA, C18, GCB, MgSO₄).
  • Custom dSPE formulations (varying PSA, C18-EC, GCB loadings and additional sorbents).
  • EMR-Lipid dispersive SPE targeting unbranched hydrocarbon chains.
• Dilution strategies (up to 20×) to reduce co-extractive interference.

Instrumentation included Agilent triple quadrupole systems (GC/MSMS 7010 and 7000, LC/MSMS 6495B), SPEX GenoGrinder for homogenization, and standard GC columns (HP-5msUI).

Main Results and Discussion

Key findings were:

• Custom 2× dSPE improved background reduction compared to single cleanup but did not fully eliminate base-sensitive pesticide losses (e.g., daminozide was not partitioned into ACN after QuEChERS salts).
• Direct ACN (1% acetic acid) extraction without salts yielded promising recoveries for labile pesticides.
• Dilution (20×) significantly reduced matrix interferences in full-scan GC/MSMS profiles, facilitating more reliable quantitation.
• EMR-Lipid sorbent effectively removed triglycerides and phospholipids from high-fat matrices (butter, avocado) while preserving organophosphate and pyrethroid pesticide signals.
• High-sensitivity triple quadrupole instruments are required when employing extensive dilution to maintain low detection limits.

Benefits and Practical Applications

Optimized workflows offer:

• Improved method robustness by minimizing cannabinoid and terpene interferences.
• Streamlined sample prep with fewer manual steps and reduced vacuum manifold usage.
• Enhanced instrument uptime and reduced maintenance due to cleaner extracts.
• Applicability across diverse cannabis-based products, including flowers, edibles, oils, and high-fat matrices.

Future Trends and Opportunities

Emerging developments include:

• Introduction of EMR-Lipid in cartridge SPE formats for automated, high-throughput workflows.
• Further customization of dispersive sorbent blends to target specific matrix classes.
• Integration of predictive matrix-effect modeling to tailor dilution and cleanup parameters.
• Expansion to multiresidue screening for mycotoxins, heavy metals, and other contaminants.

Conclusion

Careful selection and optimization of extraction, cleanup, and dilution strategies are critical for reliable pesticide analysis in cannabis and related products. Combining ACN (1% acetic acid) extraction, targeted dispersive SPE (including EMR-Lipid), and strategic dilution can overcome complex matrix interferences while preserving analyte recovery. These refined protocols support accurate, high-throughput testing in modern cannabis laboratories.