A colorimetric method for the enzymatic analysis of gases: the determination of ethanol and formaldehyde vapors using solid alcohol oxidase.
A novel enzymatic approach to the direct determination of ethanol vapors in the gas phase is described. The system is composed of alcohol oxidase, peroxidase, and the color indicator 2,6-dichloroindophenol dispersed on microcrystalline cellulose (avicel). Simple devices are developed for the semiquantitative determination of ethanol in the breath. The devices are optimized to produce a sharp color change at a set time of 1 min for ethanol concentrations above the legal limit for driving (kinetic method) or a stable final color after 5 min (equilibrium method). Such color changes are detectable by simple visual observation. Using TLC plastic sheets and a transmittance densitometer, the system can also be used as a quantitative method for the determination of ethanol or formaldehyde vapors. Dehydrated enzymes may be useful for the analysis of hazardous gases.
Barzana
E
E
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge 02139.
Klibanov
A M
AM
Karel
M
M
D015086:2,6-Dichloroindophenol; D000429:Alcohol Oxidoreductases / Q000378:metabolism; D001944:Breath Tests / Q000379:methods; D004796:Clinical Enzyme Tests / Q000379:methods*; D003124:Colorimetry / Q000379:methods*; D000431:Ethanol / Q000032:analysis; D005557:Formaldehyde / Q000032:analysis; D005740:Gases / Q000032:analysis*; D010084:Oxidation-Reduction; D013053:Spectrophotometry
D005740:Gases; D005557:Formaldehyde; D000431:Ethanol; D015086:2,6-Dichloroindophenol; D000429:Alcohol Oxidoreductases; C019643:alcohol oxidase