| 摘要 |
<p>An optical probe for the invasive measurement of the partial carbon dioxide pressure comprises an optical fiber (18)' and a pCO2 sensor (15'). The pCO2 sensor (15') comprises a diffusion zone with a dye-containing gel (23') which is optically sensitive to H<+> ions and a semi-permeable membrane (30') which is permeable to CO2 molecules, but basically not to hydrogen ions. Components of the pCO2 sensors such as the part of the optical fiber (18') extending into the sensor or a reflector (24') are covered with a substance - preferably, with a coating (35, 36) - that is basically non-permeable to hydrogen ions. This prevents the hydrogen ions from diffusing into the sensor components, which otherwise would cause an imbalance of hydrogen ions and therefore a drift in the pCO2 reading. <IMAGE></p> |
