Reducing Instrument Downtime in Elemental Analysis of Lubricant Oils as per ASTM 5185

Importance of the Topic

Elemental analysis of lubricant oils is essential for predictive and preventive maintenance as well as trend monitoring in heavy industries.
This analysis quantifies wear metals, additive elements and contaminants, offering rapid insights into oil condition and equipment health.

Objectives and Study Overview

This application note assesses the Agilent 5900 Synchronous Vertical Dual View ICP-OES paired with an Advanced Valve System 6 and a V-groove nebulizer for ASTM D5185-18 compliant analysis of lubricant oils.
The primary objective was to increase sample throughput to over 1,000 analyses in six hours (>160 samples per hour) while reducing instrument downtime from nebulizer and injector blockages.

Methodology

Used diesel engine oil samples were prepared following ASTM D5185-18, with serial dilution of organometallic standards in 75 cSt base oil and yttrium as internal standard.
Instrument parameters included radial viewing at 8 mm, 1.4 kW RF power, and a 0.25 mL loop in the AVS 6 valve configured for “first in, last out” delivery.
Wavelengths were selected to minimize interferences, employing fitted background correction or FACT for sodium at 589.592 nm.
Spike recovery, long-term stability over six hours, and method detection limits (MDLs) were evaluated.

Used Instrumentation

• Agilent 5900 Synchronous Vertical Dual View ICP-OES
• Agilent Advanced Valve System 6 (AVS 6) with 0.25 mL loop
• Agilent V-groove inert high-TDS nebulizer
• Agilent Easy-fit torch with 1.4 mm inert alumina injector
• Glass double-pass cyclonic spray chamber
• Agilent SPS 4 high-speed autosampler

Main Results and Discussion

• Achieved analysis of over 1,000 samples in six hours with no plasma shutdowns.
• Spike recoveries for all 22 elements fell within ±10% of expected values.
• Long-term stability study showed <±10% relative variation and <5% RSD precision over six hours.
• MDLs were below 1 mg/kg for most elements (except P and S), meeting ASTM D5185-18 sensitivity requirements.
• No nebulizer or torch injector blockages; inert V-groove design allowed passage of dissolved solids and particles.

Benefits and Practical Applications

• Significant reduction in instrument downtime and maintenance cycles.
• Extended run times supported by robust inert nebulizer and alumina injector.
• High-throughput capability enhances laboratory productivity and cost efficiency.
• Accurate, multi-element detection supports tribology labs in wear analysis and additive monitoring.

Future Trends and Opportunities

Ongoing developments may include integration of oxygen addition for further carbon control and adoption of advanced spectral correction software.
Automated data processing and real-time monitoring could streamline quality control workflows and expand applications to other complex matrices.
Materials advances in nebulizer and injector design will further enhance robustness for challenging samples.

Conclusion

The combination of Agilent 5900 SVDV ICP-OES, AVS 6 valve system and inert V-groove nebulizer delivers high-throughput, robust, and sensitive multi-element analysis of lubricant oils according to ASTM D5185-18.
This approach minimizes downtime from blockages, ensures stable performance over extended runs, and meets stringent detection requirements for wear metals and additives.

Reference

• 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 (ICP-AES), ASTM International, West Conshohocken, PA, 2018.
• Real-Time Spectral Correction of Complex Samples Using FACT Spectral Deconvolution Software, Agilent Technologies, publication number 5991-4837EN, 2021.