| 摘要 |
An apparatus for detecting and measuring the presence and the concentration, respectively, of halogenated hydrocarbons, in particular anaesthetic gases, as halothane, enfluorane, metoxyfluorane and isofluorane, in a mixture of gases comprises a piezoelectric crystal, which has its surface coated with a thin layer of a substrate and which is so arranged that the substrate layer can be brought into contact with the gas mixture. The crystal is coupled to an oscillator circuit which is connected to means for measuring changes in the oscillating frequency of the crystal and thus also of the oscillator circuit caused by adsorption by the substrate layer of the gas component to be detected. The substrate layer comprises a silicone oil having a structural formula comprising large branch chains or pendant blocks. Preferably a silicone oil is used comprising a silicone glycol copolymer.
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