Principle and characteristics of the ROCHE tissue pH electrode.

A miniaturized probe for continuous measurement of tissue (interstitial fluid) pH is described. The electrode design follows closely the concept described by Stamm and co-workers. The pH sensitive tip has a length of 1 mm and is made of a Li-Ba-Si glass of low electrical resistivity. The reference electrode with a capillary type liquid junction is an integrated part of the electrode assembly. This paper summarizes the important design features of the electrode and describes its in vitro characteristics.