Improved Accuracy in the Measurement of Wear Metals and Additives in Lubricant Oils by ICP-OES

Význam tématu

Lubricant oil monitoring is essential for ensuring machinery reliability and longevity. By tracking elemental profiles, laboratories and operators can detect wear metals and additive levels, enabling predictive and preventive maintenance to avoid equipment failures.

Cíle a přehled studie / článku

This application note evaluates the Agilent 5800 Radial View ICP-OES configured for ASTM D5185-18 to achieve rapid, accurate quantification of 22 elements in both used and unused lubricating oils.

Použitá metodika a instrumentace

The system comprises an Agilent 5800 RV ICP-OES with an AVS seven-port switching valve, an Easy-fit fully demountable torch with a 1.4 mm quartz injector, a SeaSpray concentric nebulizer, and an SPS autosampler.
Samples are prepared at 10 % w/w oil in A-Solv solvent with a cobalt internal standard at 25 mg/kg. Calibration standards range from 0 to 380 mg/kg for additives and up to 50 mg/kg for wear metals.

Hlavní výsledky a diskuse

Calibration linearity was excellent across the full dynamic range (R² > 0.999). Method detection limits were below 0.5 mg/kg for all elements. Outlier Conditional Formatting flagged false positives caused by Mo interferences at standard lines, while IntelliQuant identified optimal interference-free wavelengths (for example Al 167.019, Si 251.432, Sn 189.925), eliminating the need to rerun samples.
Analysis of NIST 1085c Wear Metals in Lubricating Oil SRM yielded recoveries within ±10 %. Spike recoveries in hydraulic, gear, and engine oils across different viscosities remained within ±10 %, demonstrating method robustness. A 10-hour sequence of over 700 samples showed stability with recoveries within ±10 % and precision better than 5 % RSD.

Přínosy a praktické využití metody

The approach enables single-run determination of both low-level wear metals and high-level additives, reduces remeasurements, and lowers argon consumption via the AVS valve. Smart software tools guide wavelength selection and maintenance scheduling, improving confidence in results and reducing downtime.

Budoucí trendy a možnosti využití

Future developments may include tighter integration with laboratory automation, real-time lubricant health monitoring, expansion to additional elements and matrices, and advanced predictive maintenance analytics.

Závěr

The Agilent 5800 RV ICP-OES, combined with smart diagnostic software and a demountable torch, delivers a robust, high-throughput method for ASTM D5185-18 compliant lubricant analysis, ensuring accurate results on the first measurement and minimal instrument downtime.

Reference

• ASTM International. ASTM D5185-18 Standard Test Method for Multielement Determination of Used and Unused Lubricating Oils and Base Oils by Inductively Coupled Plasma Atomic Emission Spectrometry. West Conshohocken, PA; 2017.
• Agilent Technologies. IntelliQuant Software: For greater sample insight and simplified method development. Publication 5994-1516EN.
• Amorin A. Multi-element Analysis of Used Lubricant Oils: Evaluating an Agilent Easy-fit fully demountable ICP-OES torch for oil analysis. Agilent Publication 5994-1533EN.
• Haque T, Morina A, Neville A, Kapadia R, Arrowsmith S. Non-ferrous coating/lubricant interactions in tribological contacts: Assessment of tribofilms. Tribology International. 2007;40:1603–1612.