EXPLANATION
The determination of engine oil volatility at 371° C is a requirement in some lubricant specifications. This test method is intended as an alternative to Test Methods ASTM D5800 and ASTM D5480. The data obtained by this test method are not directly equivalent to that obtained by Test Method ASTM D5800. The results by this test method can be biased by the presence of additives (polymeric materials), or by heavier base oils which may not completely elute from the gas chromatographic column. The results of this test method may also not correlate with other oil volatility methods for nonhydrocarbon synthetic oils. This test method can be used on lubricant products not within the scope of other test methods using simulated distillation methodologies, such as Test Method ASTM D2887.
This test method applicability is limited to samples having an initial boiling point greater than 126° C. This test method may be applied to both lubricant oil base stocks and finished lubricants containing additive packages. However, because of the nonelution of heavier components of these additive packages, the results by this test method are biased low compared to those by the Test Method ASTM D5480, which uses an internal standard to compensate for noneluted material.
TEST SUMMARY
A sample aliquot diluted with a viscosity reducing solvent is introduced into the gas chromatographic system which uses a nonpolar open tubular capillary gas chromatographic column for eluting the hydrocarbon components of the sample in the order of increasing boiling point. The column oven temperature is raised at a reproducible linear rate effect separation of the hydrocarbons. The quantitation is achieved with a flame ionization detector. The sample retention times are compared to those of known hydrocarbon mixtures, and the cumulative corrected area of the sample determined to the 371° C retention time is used to calculate the percentage of oil volatilized at 371° C.
TEST PRECISION
Where X is the volatility level.
Bias has not been determined.