Chemical studies on acid-base indicators for the development of an extrinsic optical fiber pH sensor

Spectrophotometric behaviour of acid-base indicators immobilized on XAD-2 microspheres are reported and an accurate comparison with the properties of the dye in liquid phase is carried out. On the basis of this study phenol red is chosen as the most suitable dye for pH detection in the physiological range (7.0-7.5). The sensor model for pH measurements is described and experimental results are discussed.