EXPLANATION
This test method covers the voltammetric determination of hindered phenol antioxidants in new or used Type HL turbine oils in concentrations from 0.0075 wt. % up to concentrations found in new oils by measuring the amount of current flow at a specified voltage in the produced voltammogram. See Test Method ASTM D6614 for further details.
TEST SUMMARY
A measured quantity of sample is dispensed into a vial containing a measured quantity of alcohol-based electrolyte solution and containing a layer of sand. When the vial is shaken, the hindered antioxidants and other solution soluble oil components present in the sample are extracted into the solution, and the remaining droplets suspended in the solution are agglomerated by the sand. The sand/droplet suspension is allowed to settle out and the hindered phenol antioxidants dissolved in the solution are quantified by voltammetric analysis. The results are calculated and reported as wt. % of antioxidant or as mmole of antioxidant per litre of sample for prepared and fresh oils, and as percent remaining antioxidant for used oils.
TEST PRECISION
Where X is the mean value.
The test method has no bias since the results of this test are defined only in terms of this test method.