Oil samples are analyzed for water content (moisture) using the Karl Fischer moisture titration. This analysis method is particularly useful at detecting both high moisture contents and trace moisture contents. The process was invented by a German chemist named Karl Fischer in 1935.

The testing process involves a chemical reaction between water and Iodine within a reagent. Iodine is dispensed into the sample in small amounts until the

reaction endpoint is reached. The amount of Iodine used in the reaction is directly proportional to the amount of water within the sample. The following

reaction takes place (in the presence of a solvent mixture):

I2 + 2H2O + SO2 → 2HI + H2SO4

Karl Fischer titration's are extremely accurate and can give results ranging from 1ppm to 100%. Another significant advantage is that unlike the conventional

Loss On Drying method (LOD), this process is not adversely affected by the presence of other volatiles - the LOD method detects the loss of any volatile

substance, not just water.