Analysis of Additive Elements in Lubricating Oil According to ASTM D4951: ICPE-9820

Significance of the Subject

Maintaining the correct concentration of organometallic additives in lubricating oils is essential for machinery performance, longevity, and quality control in automotive and industrial applications.

Objectives and Study Overview

This study demonstrates the use of Shimadzu ICPE-9820 ICP atomic emission spectrometry to quantify key additive elements (B, Ca, Mg, Mo, P, Zn) in engine oil, automatic transmission fluid, and gear oil, in accordance with ASTM D4951 and JPI-5S-38 standards.

Methodology and Instrumentation

Samples of commercial oils were diluted in xylene (1 g in 100 mL) and spiked with a 1 mg/L yttrium internal standard. A fivefold dilution test assessed recovery accuracy. Calibration employed a multi-element SPEX standard and a Conostan Y standard. The vertically oriented plasma torch of the ICPE-9820 allowed direct analysis of organic solvent samples without oxygen addition, minimizing carbon deposition at the torch tip.

• Instrument: Shimadzu ICPE-9820 multi-type ICP atomic emission spectrometer
• RF power: 1.40 kW
• Gas flow rates: Plasma 16.0 L/min, Auxiliary 1.40 L/min, Carrier 0.70 L/min
• Sample introduction: UES10 nebulizer with straight-drain misting chamber
• Observation mode: Radial

Key Results and Discussion

Quantitative analysis yielded recoveries near 100% in dilution tests for engine oil. Concentrations measured across samples:

• B: 113 μg/g
• Ca: 1,100 μg/g
• Mg: 754 μg/g
• Mo: 87 μg/g
• P: 637 μg/g
• Zn: 736 μg/g

Spectral profiles for Ca (315.887 nm) and Mo (202.030 nm) showed clear peaks for both neat and diluted samples. Calibration curves for Ca, Mo, and Zn exhibited excellent linearity (r > 0.9999).

Benefits and Practical Applications

This method enables accurate, rapid, and oxygen-free analysis of lubricating oil additives in organic solvents, simplifying laboratory workflows and reducing costs associated with oxygen supply.

Future Trends and Opportunities

Expanding this approach to other organic solvents and additional trace elements could further improve additive monitoring. Integration with automated sampling and data processing systems may enhance throughput and consistency in industrial quality control.

Conclusion

The Shimadzu ICPE-9820 delivers stable and precise determination of additive elements in lubricating oils using organic solvent dilution without oxygen, meeting ASTM and JPI standard requirements.

References

1. ASTM International. ASTM D4951: Standard Test Method for Determination of Additive Elements in Lubricating Oils by Inductively Coupled Plasma Atomic Emission Spectrometry.
2. Japan Petroleum Institute. JPI-5S-38-2003: Lubricating Oils – Determination of Additive Elements – Inductively Coupled Plasma Atomic Emission Spectrometry.