California and Oregon’s Complete Residual Pesticide Analysis using a Shimadzu LCMS-8060

Importance of the topic

The rapid expansion of medicinal and recreational cannabis legalization across the United States has created a critical need for reliable pesticide residue testing. With states like California regulating 66 pesticides and Oregon regulating 59, laboratories face varied action levels and analyte lists. A unified, high-throughput LC-MS solution can streamline testing, ensure compliance, and protect consumer safety.

Objectives and overview of the study

This study aimed to develop and validate a complete LC-MS workflow on the Shimadzu LCMS-8060 for quantifying the full California and Oregon pesticide lists in cannabis flower. Two complementary methods were designed: an APCI-LCMS MRM method for 10 pesticides traditionally analyzed by GC-MS, and an ESI-LCMS MRM method for the remaining 84 pesticides. Both methods were evaluated for sensitivity, linearity, precision, and accuracy in a cannabis matrix.

Methodology and sample preparation

Pesticide standards were spiked into blank cannabis flower extract to create matrix-matched calibration curves ranging from 1 to 2000 ng/g with 1/C weighting. Each pesticide employed one to five MRM transitions, and retention times were established using neat standards. Limits of quantitation (LOQs) were determined with signal-to-noise ratios above 10:1. Chromatographic separation minimized matrix interferences.

Instrumentation used

• Shimadzu LCMS-8060 triple quadrupole mass spectrometer
• Shimadzu Nexera X2 UHPLC system
• Atmospheric pressure chemical ionization (APCI) source
• Electrospray ionization (ESI) source

Main results and discussion

Both APCI and ESI methods achieved LOQs below California and Oregon regulatory action levels for all 94 pesticides. Calibration curves exhibited excellent linearity (R² > 0.99). Precision and accuracy were within acceptable limits, with low signal suppression across the matrix. Representative chromatograms demonstrated clear separation and robust peak shapes for both techniques.

Benefits and practical applications

Implementing the combined APCI/ESI LCMS-8060 solution offers:

• Comprehensive coverage of all regulated pesticides in a single instrument
• Elimination of separate GC-MS workflows for certain analytes
• High sensitivity and low LOQs for regulatory compliance
• Reduced sample preparation and faster turnaround time

Future trends and possibilities of use

Further developments may include adapting the workflow to additional matrices (edibles, oils), integrating high-resolution mass spectrometry for non-target screening, automating sample preparation, and linking data acquisition with laboratory information management systems (LIMS) for real-time surveillance and reporting.

Conclusion

A unified LC-MS approach using the Shimadzu LCMS-8060 with both APCI and ESI ionization effectively quantifies the full suite of California and Oregon pesticide residues in cannabis flower. The method meets or exceeds regulatory LOQs, streamlines laboratory operations, and ensures accurate, high-throughput testing.