Construction and evaluation of a disposable pH sensor based on a large core plastic optical fiber

The fabrication and characterization of a disposable optical fiber sensor for the detection of pH in the range 5–8 are described. The sensing element is a drop of sol–gel hybrid material containing phenol red and deposited onto the tip of a large core plastic optical fiber. This fiber is also exploited for the optical interrogation. This probe can be used as a disposable part of a measuring system. The dynamic range and temporal response of the sensor are here investigated