The BreathScan® works on the principle of ethyl alcohol (ethanol) in the blood partitioning with the air in the lungs, which causes it to escape via exhaled breath.
The method of detection employs potassium dichromate crystals, which are maintained in a fresh environment, within a sealed ampoule until the test is administered. When the crystals come into contatct with ethyl alcohol they cause the ethanol to be oxidised into acetic acid (vinegar), according to the equations below. When this occurs, the crystals loose oxygen atoms and undergo a corresponding colour change, which is used as an indicator to identify the presence of alcohol.
(i) Cr2O72- + 3C2H5OH + 8H+ → 2Cr3+ + 3CH3CHO + 7H2O
(ii) 2Cr2O72- + 3C2H5OH + 16H+ → 4Cr3+ + 3CH3COOH + 11H2O
test kit contains of the following inclusions:
Sealed test tube
The following instructions provide details on how to use BreathScan® to determine the blood alcohol level of a test subject.
Wait for at least 15 minutes after the last alcoholic drink (this is the time to commence absorption into the body).
Break the inner glass amplue containing the crystals by squeezing the outer plastic tube between thumb and forefinger.
Squeeze only once and don’t bend or crush the tube. Use the test immediately following activation.
The subject should take a deep breath and blow for 12 seconds in one continuous breath through the end of the tube designated by an arrow.
Ensure that no inhalation takes place.
Shake the tester to distribute crystals evenly.
After 2 minutes identify any color change amongst a majority of the crystals.
Most of the crystals remain light yellow in colour. This indicates that the breath alcohol is below the level printed on the tube.
0.02 % In the instance of a positive test, where the level of alcohol detected in the breath corresponds to a blood alcohol level of > 0.02 %, crystals within the tube will become white or ash like or aqua coloured.
0.05 % Most of crystals are a light aqua (green/blue, blue/green) cast. This shows that the breath alcohol has been detected at or above the level printed on the detector.
Note: For best results it is recommended that comparison with an unused test be made, in order to establish if a colour change has occured.
The following documents related to BreathScan®
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