| 摘要 |
<p>New measuring sensor consisting of a material which on contact with reducing gases changes its electrical conductivity is intended for use with a measuring device for determining the concentration of alcohol in the breath. In this addn. the surface of the sensor is coated with a substance which dissolves, or dissolves in alcohol more readily than gases or vapours of reducing substances, which are present in the breath and falsify the result of the measurement (esp. ketones, acetone, methane, carbon monoxide, aromatics). Used in devices (e.g. as in parent specification for measuring blood alcohol concentrations by determination of alcohol concns. in the breath. The coating reduces or eliminates false readings due to the presence of reducing substances other than alcohol in the breath. The breath of diabetics can have an acetone : ethanol ratio of ca 1:5. Coating of the sensor can reduce its sensitivity by a factor of 10, so that errors due to acetone become negligible. The material which changes its conductivity in contact with reducing substance pref. contains one or more metal oxides. The coating material is pref. water-soluble and hygroscopic, examples of suitable substances being beta-alanimine, benzyl benzoate, 8-hydroxy-5-quinoline-carboxylic acid and aluminium chloride.</p> |
