8 Keys to Oil Analysis Victory: Key #8 – Antioxidant Testing (LSV) 101

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8 Keys to Oil Analysis Victory

In power plants and other critical operations, oil condition is one of the most significant contributors to turbine reliability, yet it’s often overlooked until alarms start ringing. By the time warning signs appear, the real problem has often been developing quietly for months or even years.

The truth is simple: lubricants rarely fail suddenly. They typically fail after prolonged neglect.

Early in a lubricant’s life, few visible problems appear, making it easy to ignore the gradual chemical changes happening inside the system. Over time, however, unmanaged degradation begins to surface:

Rising MPC varnish potential
Additive depletion
Accumulation of oxidation byproducts that deposit on equipment surfaces

At EPT Clean Oil^™, our goal is simple: to teach the world a better way through Lubricant Chemistry Management. Because success in lubrication reliability doesn’t come from a single test or a single insight. It comes from understanding the lubricant’s chemistry and managing it strategically over time. That’s why we developed The 8 Keys to Oil Analysis Victory.

These eight tests form the foundation of a winning lubricant management strategy. Think of them as the core plays in your reliability playbook and the insights that allow your team to:

Understand where your lubricant is strongest
Identify weaknesses before they become failures
Make informed adjustments before equipment performance is impacted

Key #8: Antioxidant Testing (LSV)

What is Antioxidant Testing (LSV)?

Antioxidant testing is an oil analysis method used to measure the remaining protective additives in a lubricant. The most common technique, Linear Sweep Voltammetry (LSV) testing, measures key antioxidants such as amine and phenol compounds that protect oil from oxidation. Results are compared to new oil to show how much antioxidant protection remains.

Did you know? Understanding how much oxidation resistance remains in your lubricant is critical and provides insight into the overall condition of your lubricant. This is determined through the LSV test method.

Why is Antioxidant Testing (LSV) important?

Lubricants degrade over time as their additives are gradually used up. Antioxidants act as a protective defence, reacting with oxygen to prevent the base oil from breaking down. As these antioxidants are depleted, the oil becomes more vulnerable to oxidation, sludge, and varnish formation. Monitoring antioxidant levels through routine oil analysis helps maintenance teams determine how much protection remains and identify when the lubricant is nearing the end of its service life, allowing action to be taken before equipment problems occur.

How does Antioxidant Testing (LSV) work?

During LSV testing, a small oil sample is analyzed using an electrochemical instrument equipped with electrodes. The test applies a controlled voltage sweep to the sample, which causes antioxidant molecules to react at specific points during the process. By measuring the electrical response, the instrument can determine the concentration of the remaining amine and phenol antioxidants.

Results are reported as a percentage of the original antioxidant levels compared with a new oil sample of the same type and brand. Because the test is comparative, using the correct baseline sample is critical to ensure accurate interpretation.

Individual LSV results can vary slightly, typically within about 13–26% for the same sample. For this reason, results are most valuable when trended over time rather than evaluated as a single data point.

When antioxidant levels consistently fall below approximately 25% of their original value, the lubricant has typically reached the end of its effective life, and corrective action should be considered. By monitoring antioxidant depletion, maintenance teams gain a clearer understanding of lubricant health and can keep equipment operating reliably, efficiently, and protected for longer.

Learn more about Antioxidant Testing (LSV).

Stop Guessing, Start Trending

Our Fluid Technical Center team takes the routine out of oil analysis, providing a complete picture of your fluid condition to ASTM standards. Testing packages are designed for each application and performed by professional chemists, delivering accurate, actionable results.

Data is reviewed and interpreted by application specialists and PhD chemists to provide a comprehensive overview of your samples and deeper insight into root cause. As part of our ACE™ assessment, advanced Antioxidant Testing (LSV) is performed to provide deeper insight into varnish potential and overall fluid health, empowering you to make data-informed decisions about your critical assets.

It’s as easy as 1, 2, 3.