The use of tristimulus colorimetry for the determination of hydrogen cyanide in air by a modified König method

Abstract

A simple visual and tristimulus colorimetric method (three-dimensional system CIE-L*a*b*) for the determination of trace amounts of hydrogen cyanide in air has been developed. The method is based on the suction of hydrogen cyanide through a chlorinating cartridge where cyanogen chloride is formed, which is further driven to an indicator disc made of a modified cotton fabric. This indicator disc is placed into an adapter. Prior to analysis, the disc is saturated with a chromogenic reagent, a solution of 5,5-dimethyl-1,3-cyclohexanedione (dimedone) and 4-benzylpyridine in ethanol. In the presence of hydrogen cyanide (cyanogen chloride), a pink coloration emerges on the indicator disc, the intensity of which is evaluated either visually or by use of a tristimulus colorimeter. The detection limit is 0.1 mg m -3 . The method is mainly suitable for mobile field analyses. It was applied for the CHP-5 chemical agent detector introduced into the equipment of the Czech Army corps.

Recent advances in fluorescent and colorimetric chemosensors for the detection of chemical warfare agents: a legacy of the 21st century

“…11(D)). 112,113 Based on similar chemical reactions, a testing kit consisting of test bottles and test reagents was constructed to analyze the chemical agent present in aqueous media. A major limitation to chemical analysis is that the test is only as specific as the dyes used.…”

“…244 The mouse bioassay failed to distinguish between STX and TTX due to similarities in the clinical symptoms of the two toxins. 245 The selectivity of STX over TTX was demonstrated by Gawley et al using acridine-based crown ether chemosensors (112)(113). 246 However, the binding constant was similar to that of the anthracenyl derivative, suggesting a similar interaction between the host and guest.…”

“…240 Similarly, STX inhibits PeT when bisguanidinium ions bind to crown ethers via ion-dipole interactions. Molecular probes (110)(111)(112)(113)(114)(115)(116) based on several fluorophores (anthracene, coumarin, acridine, and aza-BODIPY) and crown ethers were designed and exploited for the detection of STX (Fig. 87).…”

A new detection tube to detect hydrogen cyanide in the air

“…Developing of HCN vapors took about 2 min. The actual content of HCN in the chamber was determined spectrophotometrically by a modified method according to Koenig [29]. The response of detection tubes was evaluated visually (by naked eye) based on a color change of the indication filling in dependence on the concentration of HCN in the chamber.…”