Detection and Estimation of Carbon Monoxide

Carbon monoxide may be detected by its reducing action on metallic salt solutions, the most sensitive of which is palladious chloride. The gas containing carbon monoxide is passed through a dilute solution of palladious chloridfe, when metallic palladium is precipitated according to the reaction:

PdCl₂ + CO + H₂O = 2HCl + CO₂ + Pd.

The reaction with blood serves for the detection of 0.25 per cent, of carbon monoxide in air.

Carbon monoxide is generally estimated by the loss of volume consequent upon its absorption in an ammoniacal or hydrochloric acid solution of cuprous chloride.

The gas may also be estimated by combustion, or by oxidation by iodine pentoxide at 150° C., followed by titration of the carbon dioxide after absorption in baryta water. This method, which is due to Gautier, has been elaborated by Levy.

The quantity of carbon monoxide in a mixture of this gas with hydrogen and methane may be determined by fractional combustion when the mixture is passed over palladium-asbestos at a rate not exceeding 1 litre per hour, the carbon monoxide alone being oxidised; and when a similar mixture is passed over copper oxide at 250° C. the methane is also unaffected.