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

Significance of the Topic

Trace elemental analysis of distillate petroleum products is critical to maintain catalyst performance, product quality, and regulatory compliance. Metals such as nickel, vanadium, mercury, and lead can poison catalysts at low levels, increasing operational costs and downtime. The trend toward stricter impurity limits requires highly sensitive methods capable of handling diverse sample matrices ranging from heavy crude oil to volatile naphtha.

Objectives and Overview

The study demonstrates a single quadrupole ICP-MS method following ASTM D8110 for routine analysis of crude oil and distillate fractions. Key aims include:

• Evaluating method sensitivity and specificity for 28 elements.
• Developing a unified sample preparation workflow for products with different boiling ranges and viscosities.
• Ensuring robust, uninterrupted operation during long analytical batches.

Methodology

Samples were diluted in PremiSolv: crude oil and fuel oil were heated and diluted up to 100-fold; heavy naphtha was analyzed undiluted after internal standard addition; light naphtha was diluted 10-fold. Calibration employed five standards covering 0.1–50 µg/L for trace analytes and 5–100 µg/L for potassium, with yttrium and indium as internal standards at 10 µg/L.

To prevent carbon buildup and plasma instability, pure oxygen was introduced at the spray chamber elbow. Collision-energy discrimination using helium removed polyatomic interferences. The spray chamber was cooled to –5 °C to accommodate volatile solvents.

Used Instrumentation

Analysis was performed on a Thermo Scientific iCAP MSX single quadrupole ICP-MS with:

• Cyclonic quartz spray chamber with Peltier cooling.
• iCAP MX Series nebulizer and PLUS ceramic torch.
• Additional mass flow controller for oxygen addition.
• Qtegra ISDS software with automated startup and performance checks.

Key Results and Discussion

Linearity coefficients (R²) exceeded 0.995 for all elements. Instrument detection limits ranged from 0.003 µg/L for vanadium to 55 µg/L for sodium. Spike recoveries in light naphtha and 100-fold-diluted crude oil averaged 90–110%. A 10-hour sequence mixing all sample types showed internal standards remained within 75–120% of initial values. Quality control samples analyzed every 10 runs maintained 80–120% accuracy with <5% RSD.

Benefits and Practical Applications

The method provides a single, high-throughput workflow for diverse petrochemical matrices, reducing instrument reconfiguration and downtime. Independent gas addition and rapid mode switching enable seamless transitions between aqueous and organic analyses. Robust interference removal and reliable internal standard performance support routine QA/QC in refineries and analytical labs.

Future Trends and Opportunities

Advances may include triple-quadrupole ICP-MS for improved reactive gas interference control, automated multi-mode collision/reaction gas cycling, and tighter detection limits via hydrogen reaction cells. Integrated laboratory automation will further streamline sample handling, data acquisition, and instrument maintenance.

Conclusion

A consolidated single quadrupole ICP-MS protocol per ASTM D8110 allows accurate, sensitive, and reliable quantification of 28 elements in crude oil and distillate products. The combination of cooled spray chamber, oxygen addition, helium KED, and internal standardization ensures stability and precision across varied sample types, supporting efficient petrochemical quality control.

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.
• Thermo Fisher Scientific Product Spotlight 002910. Thermo Scientific iCAP MX Series ICP-MS: Fully automatic startup and performance verification.