Analytical testing of trace elements in refinery products using a robust ICP-MS approach

Importance of the Topic

Control of trace metals such as nickel, vanadium, mercury and lead in petroleum streams is essential to prevent catalyst poisoning, reduce toxic emissions, and ensure regulatory compliance and operational efficiency.

Objectives and Study Overview

This application note presents the development of a robust ICP-MS method capable of quantifying trace elements across diverse refinery products—from high-viscosity crude and fuel oils to light and heavy naphtha—using a unified analytical approach.

Materials, Methods, and Instrumentation

Samples were prepared by xylene dilution (or direct aspiration for heavy naphtha), spiked with yttrium and indium internal standards (20 µg/L). Calibration covered 0.1–50 µg/L for most elements and 5–100 mg/L for sulfur.

• ICP-MS systems: Thermo Scientific iCAP RQ (single quad) and iCAP TQ (triple quad)
• Autosampler: Teledyne CETAC ASX-560
• Sample introduction: Quartz cyclonic spray chamber at –5 °C, PFA microflow nebulizer, quartz injector
• Auxiliary oxygen flow (20%) to control carbon deposition
• Collision/reaction gases: He (KED), H₂, O₂ and NH₃ (TQ mode)

Main Results and Discussion

Single-quadrupole analysis with He KED and H₂ achieved detection limits from sub-µg/L to low mg/L. Triple-quadrupole operation with reactive gases further suppressed polyatomic interferences, lowering sulfur detection to ~13 µg/L and vanadium to 0.001 µg/L. Accuracy was confirmed by NIST SRM 1634c (recoveries 98–105%, RSD < 5%) and spike tests in naphtha (88–113% recoveries). A 12-hour mixed-matrix batch demonstrated stable internal standard responses (90–110%) and QC recoveries within ±10%.

Benefits and Practical Applications

• One method for crude oil, fuel oils and naphtha
• Low detection limits with effective interference control
• Consistent performance over extended runs
• Simplified preparation via xylene dilution
• Supports process and quality control in petrochemical labs

Future Trends and Opportunities

Advanced triple-quadrupole ICP-MS with customizable reactive gases will drive further improvements in selectivity and sensitivity. Integration of automated sample handling, inline dilution and AI-based data correction could streamline high-throughput workflows and enhance analytical reliability.

Conclusion

A unified ICP-MS workflow combining optimized sample introduction, dynamic cell gas strategies and triple-quadrupole filtering delivers low detection limits, high accuracy and long-term stability for trace element analysis across refinery products, meeting stringent industry requirements.

Reference

• NIST SRM 1634c, Trace Elements in Fuel Oil (NIST, Gaithersburg, MD, USA)