title: Development of a Hydrogen Sulfide End-of-Service-Life Indicator for Respirator Cartridges Using Cobinamide.
abstract: An inexpensive paper-based sensor was developed for detecting low ppm concentrations of hydrogen sulfide gas. A piece of filter paper containing aquohydroxocobinamide [OH(H2O)Cbi] was placed on the end of a bifurcated optical fiber, and the reflectance spectrum of the OH(H2O)Cbi was monitored during exposure to 10.0 ppm hydrogen sulfide gas (NIOSH recommended exposure limit). Reaction of sulfide (HS-) yielded an increase in reflectance from 400-450 nm, and decrease from 470-550 nm. Spectral changes were monitored as a function of time at 25, 50, and 85% relative humidity. Spectral shifts at high-er humidity suggested reduction of the Cbi(III) compound. The sensor was used to detect hydrogen sulfide breakthrough from respirator carbon beds and results correlated well with a standard electrochemical detector. The simple paper-based sensor could provide a real-time end-of-service-life alert for hydrogen sulfide gas.
authors.forename: Lee A
authors.initials: LA
authors.lastname: Greenawald
authors.forename: Gerry R
authors.initials: GR
authors.lastname: Boss
authors.forename: Aaron
authors.initials: A
authors.lastname: Reeder
authors.forename: Suzanne
authors.initials: S
authors.lastname: Bell
keywords: Aquohydroxocobinamide; Diffuse Reflectance; End-of-Service-Life Indicator; Hydrogen Sulfide; Optical Sensor