A bundle of fiber-optic sensors that resist breakage, for use in measuring pH, CO₂, and O₂ concentration, and a method of making the same. Three optical fibers (15,17,19) are enclosed in a common polyimide sheath (13) and extend parallel to one another toward a distal end of the sensor, where they are bonded together in a mutually supportive array. At the distal end of one of these optical fibers is disposed a pellet (21) comprising a CO₂ analyte indicator molecule codissolved within a polymer matrix (22). A thin reflective surface of gold foil (20) is provided on the pellet such that incident light transmitted through the optical fiber and polymer matrix is reflected back into the optical fiber. The CO₂ polymer matrix absorbs light of a given wavelength to an extent dependent upon the level of CO₂ present. Similarly, on the distal end of a second optical fiber is disposed a pH pellet (25) comprising a pH analyte indicator matrix with a thin reflective gold foil (24) attached for reflecting light that has passed through the pH analyte indicator matrix back into the optical fiber. The pH analyte indicator matrix absorbs light of a given wavelength to an extent dependent upon the hydrogen ion concentration (pH level) of a surrounding fluid. The third optical fiber is used for measuring oxygen concentration. An O₂ indicator matrix (27) covers the distal ends of at least two of the three optical fibers; however, at least a portion of the pH optical fiber and the pH pellet are free of the O₂ indicator matrix, which is hydrophobic. The oxygen indicator matrix phosphoresces for an interval of time that decreases in proportion to the surrounding oxygen gas concentration. The phosphorescent and reflected light signals are transmitted to light detectors through the optical fibers for comparison to reference signals, so that the analyte concentrations can be determined.
一种用于测量 pH 值、CO₂ 和 O₂ 浓度的抗断裂光纤传感器束及其制造方法。三根光纤(15、17、19)被包裹在一个共同的聚
酰亚胺护套(13)中,并相互平行地向传感器的远端延伸,在那里它们被粘合在一起,形成一个相互支撑的阵列。在其中一根光纤的远端放置了一个颗粒 (21),该颗粒包括一个溶解在聚合物基质 (22) 中的 CO₂ 分析指示剂分子。小球上有一个薄薄的
金箔反射面(20),这样,通过光纤和聚合物基质的入射光就会反射回光纤。CO₂ 聚合物基质对特定波长光线的吸收程度取决于 CO₂ 的含量。同样,在第二根光纤的远端放置了一个 pH 颗粒(25),该颗粒由 pH 分析物指示剂基质组成,基质上附有薄的反射
金箔(24),用于将穿过 pH 分析物指示剂基质的光反射回光纤。pH 分析物指示基质吸收特定波长的光的程度取决于周围流体的氢离子浓度(pH 值)。第三根光纤用于测量
氧气浓度。O₂ 指示基质 (27) 覆盖了三根光纤中至少两根光纤的远端;但是,pH 光纤和 pH 颗粒的至少一部分没有 O₂ 指示基质,因为 O₂ 指示基质是疏
水性的。氧指示基质会在一定的时间间隔内发出
磷光,
磷光的衰减与周围
氧气浓度成正比。
磷光信号和反射光信号通过光纤传输到光检测器,与参考信号进行比较,从而确定分析物浓度。