Mokhov Shinkarenko Tube

Inside these tubes, there is an indicator reagent in the form of a dry packing, so the device can be used when needed without any additional preparation, which explains the fact that today the Mokhov-Shinkarenko tube is widely used in many countries around the world. Vapors of ethyl alcohol contained in alcohol, acting on the reagent, lead to the reduction of hexavalent chromium ions to trivalent ones, causing its color to change from yellow or orange to green. This change indicates a positive reaction to the presence of alcohol in the vapors exhaled by a person.

Even considering that this method is relatively non-specific, the advantage of indicator tubes over other chemical test methods is that there is no reaction to the vapors of many other substances, including poisons and medications. The color change of the reagent to green occurs only when interacting with vapors of a limited list of substances, including:

• Ethyl or methyl alcohol;
• Acetone;
• Ether;
• Hydrogen sulfide;
• Aldehydes.

When interacting with substances such as turpentine, gasoline, acetic acid, camphor, phenol, or dichloroethane, the reagent color becomes brownish, and under the influence of vapors of menthol, validol, ammonia, kerosene, chloroform, chloranhydride, alkalis, ethylene glycol, as well as ordinary water or clean air, the reagent color remains orange.

Indicator tubes can only be used once, and their use involves several simple manipulations. Before using the tube, two cuts should be made on it using a file: near the wide melted end of the device and near the cone-shaped seal. Then both cut ends should be broken off, after which a polyethylene dosing bag is placed on the end closest to the reagent, and a sterile mouthpiece is placed on the opposite end.

The person being examined should take this mouthpiece into their lips and begin intense continuous exhalation of air until the bag is filled. A positive reaction is recorded if the reagent turns green within one to two minutes from the start of blowing. A partial color change of the indicator from orange to green also indicates a positive reaction.