Development of a cobinamide-based end-of-service-life indicator for detection of hydrogen cyanide gas

• Published in: Sensors and actuators. B, Chemical Vol. 221; pp. 379 - 385
• Main Authors: Greenawald, Lee A., Snyder, Jay L., Fry, Nicole L., Sailor, Michael J., Boss, Gerry R., Finklea, Harry O., Bell, Suzanne
• Format: Journal Article
• Language: English
• Published: Switzerland Elsevier B.V 31-12-2015
• Subjects: Cobinamide; Diffuse reflectance; End-of-service-life indicator; Exposure; Hydrogen cyanide; Optical sensor; Paper sensor; Reflectance; Reflectivity; Relative humidity; Respirators; Sensors; Spectra; Hydrogen cyanide; Optical sensor; Diffuse reflectance; Paper sensor; End-of-service-life indicator; Cobinamide
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2015.06.085

•Monocyanocobinamide fixed on porous paper substrate binds gaseous HCN.•Paper substrate is positioned at end of fiber optic in diffuse reflectance setup.•Diffuse reflectance of monocyanocobinamide is monitored as a function of time and concentration of HCN.•Detection of 5.0ppm HCN possible within 10s.•Sensor is more sensitive with increasing relative humidity.
We describe an inexpensive paper-based sensor for rapid detection of low concentrations (ppm) of hydrogen cyanide gas. A piece of filter paper pre-spotted with a dilute monocyanocobinamide [CN(H2O)Cbi] solution was placed on the end of a bifurcated optical fiber and the reflectance spectrum of the CN(H2O)Cbi was monitored during exposure to 1.0–10.0ppm hydrogen cyanide gas. Formation of dicyanocobinamide yielded a peak at 583nm with a simultaneous decrease in reflectance from 450–500nm. Spectral changes were monitored as a function of time at several relative humidity values: 25, 50, and 85% relative humidity. With either cellulose or glass fiber papers, spectral changes occurred within 10s of exposure to 5.0ppm hydrogen cyanide gas (NIOSH recommended short-term exposure limit). We conclude that this sensor could provide a real-time end-of-service-life alert to a respirator user.