Three-minute method to check for impurities in gasoline

Suspecting that the quality of gasoline was adulterated, Mr. Bui Ba Vy, Thong Hiep Alcohol Company (Hanoi) came up with a method to quickly test the total content of methanol, ethanol, propanol, butanol and acetone in gasoline using water.

Check gasoline with water

According to Mr. Bui Ba Vy, currently the Vietnamese standard TCVN 7332:2006 (gas chromatography method) is used to test alcohol types in gasoline. This is a method with high accuracy (0.01%), determining the content of each type of alcohol but the testing time is long, requiring it to be performed in a laboratory. Moreover, gas chromatography is a very expensive device, only qualified and trained people can use it and the testing cost is high. In the requirement of on-site testing, the testing time gives quick results, there is currently no method, especially a method for consumers to check for gasoline containing methanol, ethanol, acetone....

Regarding his method of testing gasoline with water, Mr. Vy explained that this invention is used to test the quality of all types of gasoline to determine the total content of methanol, ethanol, propanol, butanol, and acetone in gasoline. Alcohols with long carbon chains (more than 5), from pentanol and above, are insoluble in water, so this method cannot be applied.

The author explains the principle that water does not dissolve in gasoline, but methanol, ethanol, propanol, butanol (these belong to the alcohol group) and acetone are easily soluble in water. The above substances with high purity (ie low water content), they can dissolve in gasoline to create a gasoline - alcohol / acetone mixture that does not separate. When water is added, the gasoline - alcohol / acetone mixture will separate into two very clear layers. Gasoline is in the upper layer, the lower layer is alcohol / acetone and water.

To prove it, Mr. Vy tested the quality of gasoline using this method. Accordingly, the test is quite simple with normal domestic water or distilled water and the testing tool is a 30ml test tube with a volume marking.

Mr. Vy is pointing out the separation and cloudiness of gasoline.

Easy to do

The procedure is carried out in 3 steps. Step 1: Pour water into the test tube up to the 5ml mark. Step 2: Continue to add 20ml of the gasoline to be tested. Step 3: Cover the end of the test tube tightly and shake vigorously until the water and gasoline are mixed together (turn the test tube upside down and shake vigorously about 5 times or more).

After shaking well, stand the test tube upright again, the solution in the test tube will separate into two clear layers. Gasoline floats on top (has the characteristic color of each type of gasoline), the mixture of water and alcohol/acetone lies below.

If the gasoline does not contain alcohol/acetone: The gasoline floating on top of the test tube will be clear, not cloudy, and the water level in the test tube will not exceed 5ml (initial water level).

In case the gasoline sample is mixed with impurities, the gasoline floating on top of the test tube will be cloudy (cloudy "like boiled mussel water" in folk terms) and the water level in the test tube will be higher than the initial 5ml. This volume difference is the amount of alcohol/acetone in 20ml of gasoline.

Mr. Bui Ba Vy said that the advantage of this method is that after only about 3 minutes, the results are available with relatively high accuracy (the test's detection ability is at least 0.5% alcohol/acetone content in gasoline). This method is simple, the testing cost is low, and does not require complicated machinery, so consumers can do it themselves.

According to Kienthuc-M