Find Out How Breathalyzer Works
Have you ever wondered how policemen know that the alcohol content in a driver’s blood is higher than the required limit? This is through the power of a portable breathalyzer. Derived from the word “breath”, this device can measure the blood alcohol content by breathing that is why it is also known as breath alcohol tester. This scientific method has helped a lot of people by getting rid of drunken drivers on the road. Though these drivers are aware on the dangers they put themselves and pedestrians into, they still forced their selves to drive. Good thing, policemen are always on the lookout and alert of these kinds of drivers.
But what is the science behind a breathalyzer? How can it measure the alcohol content? It has been known that alcohol is not digested and ingested in the body. It is only absorbed by the tissues in a person’s mouth, throat, intestines and stomach, and they are excreted. As the blood flows, some alcohol goes through the membranes of the air sacs into the air. This is called alveolar air. Because alcohol is volatile, meaning it does not mixed with other liquid, it is then evaporated. Thus, the alcohol concentration in the air sacs is similar to the concentration of alcohol in the blood. When the air from the lungs is exhaled, it can easily detected by the breathalyzer.
The breathalyzer uses electrochemical fuel technology that easily identifies the alcohol from the person’s breath. The alcohol in the person’s breath is detected through a chemical solution that changes in color. The alcohol content is determined by what color it changes.
The breathalyzer has a cylinder with two vials. This cylinder has a mixture of water, silver nitrate, potassium dichromate and sulfuric acid. The person breathed to this device for two to four seconds. The silver nitrate speeds up the reaction while the sulfuric acid in the device removes the alcohol from the breath absorbs into a liquid solution. The liquid solution interacts with potassium dichromate which breaks it down to chromium sulfate, acetic acid, potassium sulfate and water. During this chemical reaction, there is a change in color. Potassium dichromate is reddish- brown and when it reacts with the alcohol, it turns into green chromium ion. The level of the alcohol determines the degree of the color change.
This chemical process is done in one vial and the other vial remains in its untouched state with its unreacted mixture, which is part of the photocell system. This system has an electric current that moves the needle in the meter. The operator of the breathalyzer waits for the needle to stop moving and when it stops, the operator turns the knob to make the needle return to its resting place. The more the operator turns the knob, the higher the alcohol content.
Breathalyzer is considered to be the most accurate device in determining alcohol level. So, policemen or any law enforcements should be capable and knowledgeable in handling this device. It should also be well- maintained to avoid errors during the test. This is a must because the result from a breathalyzer is used as evidence in the court.