ASTM D565 is a standard laboratory test method used to determine the water content in petroleum products by distillation.
The test measures water content. The test principle is distillation with a water-immiscible solvent (e.g. toluene or xylene) amd the result unit is volume percent (% vol) water.
ASTM D565 is typically applied to crude oil, fuel oils, lubricating oils and other petroleum products, (especially dark or heavy samples).
The sample is mixed with a solvent. This mixture is heated and distilled. Water separates from the solvent and the collected water is measured in a graduated trap
The method is
Suitable for heavy or contaminated oils
Not affected by additives or solids that can interfere with chemical methods
Often referenced in oil & gas specifications and contracts
This test method is applicable to white mineral oil to check its conforniance to standard of quality required for pharmaceutical use as defined by the U.S. Pharmacopeia and the National Formulary, or the Food and Drug Administration.
Precision
This os a pass-fail test and no sestimates of precision or bias can be made
Test
The mineral oil is treated with concentrated sulfuric acid under prescribed conditions and the resulting color is compared with a reference standard to determine whether it passes or fails the test. When the oil layer shows no change in color and when the acid layer is not darker than the reference standard colorimetric solution, the oil is reported as passing the test. A blu-ish haze or a slight pink or yellow color in the oil layer should not be interpreted as a change in color.
