ASTM D4377 Standard Test Method for Water in Crude Oils by Potentiometric Karl Fischer Titration
3. Summary of Test Method
3.1 After homogenizing the crude oil with a mixer, an aliquot of the crude, in a mixed solvent, is titrated to an electrometric end-point using Karl Fischer reagent.
4. Significance and Use
4.1 A knowledge of the water content of crude oil is important in the refining, purchase, sale, or transfer of crude oils.
5. Interferences
5.1 A number of substances and class of compounds associated with condensation or oxidation-reduction reactions interfere in the determination of water by Karl Fischer. In crude oils, the most common interferences are mercaptans and sulfides. At levels of less than 500 µg/g (ppm) (as sulfur) the interference from these compounds is insignificant. For more information on substances that interfere in the determination of water using the (Karl Fischer reagent) titration method see Test Method E203.
