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.

Development of an Inexpensive RGB Color Sensor for the Detection of Hydrogen Cyanide Gas

“…In previous studies, glass fiber filter paper demonstrated larger reflectance signals than cellulose filter paper, presumably because the glass fiber paper is thicker and allows more light to reach the detector in a reflectance configuration. , Additionally, glass fiber paper is less affected by water vapor. The optimal concentration and volume of CN­(H 2 O)­Cbi placed on the paper was found to be 15.00 ± 0.02 μL of 200.0 ± 0.2 μM.…”

“…A previously described diffuse reflectance configuration comprising a bifurcated optical fiber, Ocean Optics miniature spectrometer, and tungsten halogen light source was used here to determine the normalized intensity of the chip-LED. , The common end of the bifurcated fiber optic was held close to the LED at different angles, to capture the average LED spectrum ( n = 3) by the spectrometer. Spectral responsivity of the on-chip LED was determined by holding a mirror directly above both the chip-LED and photodiodes and recording the RGB values.…”

“…We have previously shown that diffuse reflectance of cobinamidea vitamin B 12 derivativeimmobilized on cellulose and glass fiber filter paper is an effective and inexpensive AESLI prototype for detecting hydrogen cyanide (HCN) and hydrogen sulfide (H 2 S) gas. , However, miniaturization and fabrication of spectrometers may be difficult and expensive. Color sensors are an economical and easily miniaturized alternative, where light is separated into a set of colors, primarily red (R), green (G), and blue (B) .…”

Studies on the Reduction of Dehydroascorbic Acid by Glutathione in the Presence of Aquahydroxocobinamide

“…The absence of 5,6‐dimethylbenzimidazole provides Cbi‐enhanced ligand binding and redox properties , . Cbi complexes are investigated as antidotes of cyanide, hydrogen sulfide, hypotensive, and wound‐healing drugs as well as cyanide and hydrogen sulfide sensors.…”

Magnetism based electrochemical immunosensor for chiral separation of amlodipine

“…Electrochemical immunoassay, which possesses the advantages of potential portability [13], low cost [14] and high sensitivity [15], has been well developed and widely applied to chemical analysis [16,17]. Moreover, magnetic beads (MBs) are extensively selected to fabricate biosensors, which benefit from their high agent immobilization due to their small-size effect, high large surface area [18], biological compatibility and various functional groups coating.…”