ASTM D6304: Water Content, Karl Fischer (Coulometric) of Oils

ASTM D6304 Determination of Water in Petroleum Products, Lubricating Oils and Additives by Coulometric Karl Fischer Titration

The quantity of water in new oil may be an indication of its quality and predicted performance characteristics. The quantity of water in service oil may be an indication of its remaining useful life. Water can hasten the breakdown, oxidation and sludge formation of oil, potentially causing the oil to no longer protect the components that it is meant to protect. This method is useful for determining low levels of water in petroleum products, hydrocarbon solvents and automatic transmission fluids.

The reaction of water in the sample with Karl Fischer (iodine-containing) reagent electrochemically generated in the titration vessel is followed coulometrically. The water content of the sample is reported in mg water per kg sample (ppm by weight).

Related Coulometric tests offered by Petro-Lubricant Testing Laboratories:

For hydrocarbons and petroleum products including lubricating oils, consider this test method

For volatile solvents and chemical intermediates in paint, varnish, lacquer and related products, consider ASTM D1364 Water in Volatile Solvents (Fischer Reagent Titration Method)

For electrical insulating fluids consider ASTM D1533 Water in Insulating Liquids by Coulometric Karl Fischer Titration

For other organic liquids consider ASTM E1064 Water in Organic Liquids by Coulometric Karl Fischer Titration

Petro-Lubricant Testing Laboratories offers four types of tests to determine water contents. Consider a coulometric method, (such as this one) when very low levels of water are expected (10 to 25,000 ppm). Consider a potentiometric method (see ASTM D4377 Water in Crude Oils by Potentiometric Karl Fischer Titration) when slightly higher levels of water are predicted (0.2 to 2%). Consider a distillation method (see ASTM D95 Water in Petroleum Products and Bituminous Materials by Distillation) for higher levels of water (up to 25%) and consider the centrifuge method ASTM D1796 Water and Sediment in Fuel Oils by Centrifuge Method (Laboratory Procedure) ) for even higher levels of water (up to 30%) or if both water and sediment are of interest.