Can Oil Sample Container Transparency Affect the MPC Varnish Potential Results ?

We at EPT Clean Oil were shipping Sample Bottles to a Turbo Compressor User and he asked me why you are sending it to us , we have it on-site?

I emphasized Sample Bottle Should be " Not " Transparent.

He asked me Why ? We have been doing Turbine oil analysis for many years and no body asked us to do it ...

My Answer:

As per ASTM D4378-21 Standard Test Method for Measurement of Lubricant Generated Insoluble Color Bodies in In-Service Turbine Oils using Membrane Patch Colorimetry (astm.org) Standard Test Method for Measurement of Lubricant Generated Insoluble Color Bodies in In-Service Turbine Oils using Membrane Patch Colorimetry ==>

NOTE 1—The sample container used shall preclude exposure to UV light as oil is known to be sensitive to both indoor and outdoor sources.

Fluorescent light is known to contain UV components and has been shown to increase deposit levels. This exposure can occur upon drawing of the sample as well as during incubation period. Wide-mouth laboratory quality amber high-density polyethylene (HDPE) bottles have been shown to protect the oil sample from UV light exposure. Other translucent or clear sample bottles are acceptable for use provided that the sample bottle, upon drawing of the sample and throughout the heating/incubation process, is immediately placed and stored into packaging or a storage unit that blocks light. Cylindrical cardboard packaging containers meet this intent.

Higher than usual MPC Varnish Potential values and false results are expected when you place your sample under UV light with transparent sample containers.

While some maybe like it to have higher values on oil analysis results , we at EPT Clean Oil never like such false negatives to occur for a critical asset condition monitoring data...