Agilent ICP-MS Journal (August 2022, Issue 89)

Significance of the Topic

The August 2022 issue of the Agilent ICP-MS Journal highlights advances in tandem mass spectrometry (ICP-MS/MS) and new guidelines for elemental analysis across geochemistry, proteomics, pharmaceuticals, cannabis testing, and fertilizer regulation. This collection demonstrates how triple quadrupole ICP-MS expands analytical capabilities by resolving challenging interferences, enabling in situ isotopic dating, trace-level quantification, and compliance with evolving regulatory standards.

Objectives and Overview

This issue presents five practical applications and regulatory updates:

• Laser ablation (LA) ICP-MS/MS for in situ Sr isotope analysis and Rb-Sr geochronology
• Capillary LC-ICP-MS/MS for absolute protein quantification and mass purity certification
• Revised ICH Q3D(R2) and USP <232> guidelines for elemental impurities in pharmaceuticals
• ASTM D37 standard method for multi-element ICP-MS analysis of cannabis and hemp
• New EU Fertilizing Products Regulation 2019/1009 and methods for monitoring major, nutrient, and contaminant elements

Methodology and Instrumentation

Advanced ICP-MS/MS workflows and reagents were employed to resolve spectral interferences and achieve trace-level detection:

• LA-ICP-MS/MS: Agilent 8900 ICP-QQQ with sulfur hexafluoride cell gas separates 87SrF+ from 87Rb+. Laser parameters: 50–75 µm spot, 2–2.5 J/cm2, 12 Hz.
• Capillary LC-ICP-MS/MS: Flow-rate-controlled nebulization, O2 reaction gas to convert 32S+ to 32SO+, and CO2 addition to stabilize carbon load throughout gradient separation.
• ICP-MS for elemental impurities: Multi-element analysis of drug products using collision/reaction cell and triple quadrupole addressing Class 1–3 PDE limits.
• Cannabis analysis: Microwave digestion protocol developed with CEM Corporation; multi-element ICP-MS method covering As, Cd, Hg, Pb and additional elements as needed.
• Fertilizer compliance: Standard ICP-MS for major and trace elements; HPLC-ICP-MS for Cr(VI) and inorganic As speciation under new EU regulations.

Main Results and Discussion

In situ LA-ICP-MS/MS measurements of 87Sr/86Sr ratios in apatite and biotite agree within uncertainty to MC-ICP-MS and published ages, demonstrating ~1 Ma precision on 90 Ma samples. Rb-Sr isochrons from laser ablation yield ages consistent with conventional methods, confirming the method’s reliability and rapid ~1 min analysis time per spot.

Protein standards (BSA, transferrin, β-casein, cytochrome C) were quantified by capLC-ICP-MS/MS using both internal (methionine) and external (SO42–) calibration. Results (92–99 % mass purity) matched manufacturer specifications, validating traceable, species-independent quantification at femtomole levels.

The revised ICH Q3D(R2) introduces higher PDE limits for several elements and new cutaneous limits. EU Fertilizing Products Regulation 2019/1009 defines nutrient labeling and contaminant thresholds, requiring Cr(VI) and inorganic As speciation methods due by 2025.

ASTM D37 approved the ICP-MS method for cannabis matrices, standardizing sample digestion and multi-element analysis and facilitating global harmonization of heavy metal testing.

Benefits and Practical Applications

Tandem ICP-MS enables:

• Micron-scale geochronology without chemical separation, accelerating rock dating in petrography and mineral exploration.
• Absolute, traceable protein purity certification for biopharmaceutical standards and quality control.
• Streamlined pharmaceutical impurity testing aligned with updated ICH/USP guidelines.
• Reliable heavy metal screening in cannabis/hemp, supporting regulatory compliance and consumer safety.
• Comprehensive fertilizer quality monitoring, covering macro- and micronutrients, contaminants, and speciation of regulated forms.

Future Trends and Opportunities

Continued development of reactive cell gases and coupling to emerging separation techniques (e.g., microflow LC, LA-ICP imaging) will expand ICP-MS/MS applications into nanoscale speciation, single-cell analysis, and real-time environmental monitoring. Further harmonization of global regulatory standards for elemental impurities and complex matrices will drive method standardization and certification of novel reference materials.

Conclusion

The August 2022 Agilent ICP-MS Journal showcases the versatility of ICP-MS/MS for diverse analytical challenges. By overcoming traditional spectral interferences and integrating with laser ablation and chromatographic separations, these methods offer rapid, accurate, and regulatory-compliant solutions for geochemistry, life sciences, pharmaceuticals, cannabis testing, and agriculture.

References

1. Villa IM et al, Geochim Cosmochim Acta 2015 164 382–385
2. Yang YH et al, Chem Geol 2014 385 35–55
3. Walawender M et al, GSA Memoir 1990 174 1–18
4. Fernandez SD et al, Anal Chem 2012 84 5851–5857
5. Nosti AJ et al, Agilent publication 5994-5073EN
6. ICH Q3D(R2) Elemental Impurities, ICH 2022
7. EUR-Lex 32019R1009 EU Fertilizing Products Regulation