WCPS: Multi-elem ent Analys is of Cannabis us ing the Agilent 7800 ICP-MS

Significance of the Topic

The legalization of cannabis for medicinal and recreational use worldwide has driven the need for reliable quality control to detect toxic inorganic contaminants such as arsenic, cadmium, lead, and mercury. Multi-element profiling is essential to ensure consumer safety, meet regulatory requirements, and support labeling and product consistency.

Study Objectives and Overview

This study aimed to evaluate the performance of the Agilent 7800 ICP-MS equipped with High Matrix Introduction (HMI) for quantifying 25 elements in cannabis plant materials and derived products. The analysis covered raw plant samples, tinctures, creams, and CBD oils to assess method robustness across diverse matrices.

Methodology and Instrumentation Used

Sample Preparation:

• Microwave-assisted acid digestion with a mixture of HNO3 and HCl.
• Inclusion of HCl to stabilize silver and mercury in solution.

Instrumentation:

• Agilent 7800 ICP-MS with HMI autosampler and Micromist concentric nebulizer.
• Quartz spray chamber and torch with 2.5 mm injector.
• RF power set at 1600 W; helium cell gas for interference reduction; half-mass correction enabled in MassHunter software to address rare earth element doubly charged interferences.
• Internal standards (e.g., 6Li, 45Sc, 72Ge) and multilevel calibration from sub-ppb to ppm levels.

Main Results and Discussion

Calibration and Quality Control:

• Calibration curves for As, Cd, Pb, and Hg displayed excellent linearity (R2 ≈ 1.000).
• Continuing calibration checks and NIST SRMs (1547, 1573a, 1575, 1645a) confirmed recoveries within ±10%.

Elemental Findings:

• Most elements matched certified reference values with good accuracy.
• Elevated levels of As (up to 160 ppb), Cd (11.3 ppb), Pb (24 ppb), and V (143 ppb) were detected in certain cannabis samples.

Interference Management:

• Half-mass correction effectively mitigated rare earth doubly charged interferences impacting As and Se measurements.

Benefits and Practical Applications

The Agilent 7800 ICP-MS with HMI offers:

• High sensitivity and wide dynamic range for trace and major elements.
• Robust handling of high-matrix samples with minimal dilution.
• Quick Scan semiquantitative capability for broad elemental screening.

Future Trends and Potential Applications

Anticipated developments include:

• Enhanced automation for sample preparation and data processing.
• Improved interference correction strategies for complex matrices.
• Expansion to speciation studies and coupling with chromatography for comprehensive profiling.
• Broader adoption in pharmaceutical, agricultural, and regulatory laboratories.

Conclusion

The Agilent 7800 ICP-MS with HMI proved to be a reliable, accurate, and efficient tool for multi-element analysis of cannabis and related products, ensuring compliance with safety standards and supporting product quality.

References

• Branca MA. Cannabis Analysis Takes Off. C&EN Sponsored Content. August 2017.
• Filipiak-Szok A, et al. J Trace Elem Med Biol. 2015;30:54–58.