Highly sensitive analysis of distillate products per ASTM Method D8110 using single quadrupole ICP-MS

Importance of the Topic

In the petrochemical industry, precise monitoring of trace elements in distillate products is essential for ensuring product performance, meeting regulatory standards, and protecting processing equipment from corrosion or fouling. Growing demands for lower detection limits and robust analysis across a variety of matrices highlight the need for reliable routine methodologies.

Objectives and Study Overview

The study aimed to demonstrate a single quadrupole ICP-MS method compliant with ASTM D8110 for the sensitive and accurate determination of elemental impurities in crude oil, light naphtha (40–60 °C boiling range), and heavy naphtha (160–180 °C boiling range). Key performance metrics such as accuracy, precision, and long-term stability were assessed across these distillate matrices.

Methodology and Instrumentation

• Sample Preparation: Crude oil samples were heated to 40–60 °C and diluted 25–100-fold with organic solvent (PremiSolv) plus internal standards. Light naphtha was diluted 10-fold, while heavy naphtha was analyzed undiluted after internal standard addition.
• Instrumental Setup: Analysis employed the Thermo Scientific iCAP MSX ICP-MS equipped with an iCAP MX series nebulizer, cyclonic quartz spray chamber, PLUS torch, and platinum-tipped interface cones.
• Analytical Conditions: RF power at 1550 W, auxiliary gas at 0.8 L/min, cool gas at 14 L/min, nebulizer flow at 0.455 L/min, sampling depth 7 mm. Kinetic energy discrimination (KED) with helium (4.3 mL/min) in the QCell CRC enabled efficient removal of polyatomic interferences.

Results and Discussion

Calibration curves for 28 elements exhibited correlation coefficients (R²) above 0.995. Instrument detection limits ranged from 0.004 to 55.6 µg/L, depending on the element. Spike recovery experiments in light naphtha, heavy naphtha, and crude oil yielded accuracy between 80–120% for all target analytes (with potassium spiked at 50 µg/L). Over a continuous 10-hour batch containing mixed distillate samples, internal standard signals varied within 75–120% of initial values, demonstrating robust performance.

Benefits and Practical Applications

By combining a versatile sample introduction system, a robust plasma source, and effective interference removal, the described method offers laboratories a streamlined workflow for multi-matrix elemental analysis. It supports accurate quantification of a broad suite of elements in petrochemical distillates, facilitating routine quality control and regulatory compliance.

Future Trends and Applications

Advancements may include expanded use of reactive gases (e.g., hydrogen) for targeted interference reduction, automated dilution strategies to handle diverse viscosities, and integration with digital data platforms for real-time monitoring. The flexibility of the iCAP MSX design also enables rapid adaptation to emerging fuel types and regulatory requirements.

Conclusion

The single quadrupole ICP-MS method following ASTM D8110 delivers sensitive, accurate, and robust analysis of elemental impurities in distillate products. Its proven performance across light naphtha, heavy naphtha, and crude oil supports efficient, routine application in petrochemical laboratories.

References

• Thermo Fisher Scientific Application Note 44465: Addressing the challenges of routine determination of elemental impurities in refinery products using a robust ICP-MS approach