A new detection tube to detect hydrogen cyanide in the air

A new simple and sensitive detection tube to detect hydrogen cyanide in the air has been developed. The detection tube is based on the reaction of hydrogen cyanide with 4-nitrobenzil to form a violet colored product. The reaction takes place on the carrier made of a composite material which was prepared by pelletization of a mixture of microcrystalline cellulose and MgO. The detection tube can detect hydrogen cyanide in the air in the range of concentrations 0.1-100 mg.m-3 based on visual evaluation (by naked eye) of the change of indication layer coloring and comparison with etalon. The detection limit is 0.05 mg.m-3. The detection tube is highly selective and sufficiently stable during storage.