Method of determining water and alcohol content in gasoline

Water detection in gasoline and diesel fuel

Gasoline, diesel fuel, and water will normally separate into distinct phases if allowed to settle. The water will remain at the bottom of the tank, with the fuel above. Water finder pastes are used with gauge sticks to determine if water is present in a fuel tank, and to determine the level of water as well. The water finder paste is applied to the bottom of a gauge stick and slowly lowered into the fuel tank. The water finder paste will change color in the presence of water, while the paste will not be affected by gasoline or diesel fuel. Fuel tanks should be checked regularly for water and sediment, which should be evacuated to avoid equipment operating problems. This becomes especially crucial while operating in freezing temperatures, when both fuel bulk tanks and equipment tanks should be regularly monitored.

Ethanol Detection - Water Extraction Method

Alcohol can be detected in gasoline using the Water Extraction Method, in which alcohol blended with gasoline will react differently with water then unblended gasoline. A gasoline sample should be taken in a glass vessel, after which water should be slowly added to the container to a level of approximately two inches. Once the gasoline and water have settled and distinctly separated, the container should be marked at the phase separation point. Once the container is clearly marked, it should be agitated for one minute, after which the contents should again be allowed to settle. An alcohol blended gasoline will show a larger lower phase at this point, due to a phase separation of the ethanol and gasoline. In effect, the lower phase is now water and ethanol with the upper phase of gasoline. Once the ethanol and gasoline are separated, they cannot be reblended via agitation; this phase separation is a one way process. If the sample is pre gasoline, the water will settle at the previously marked level, with no apparent increase in the lower phase of the container.