A NEW INSTRUMENT FOR THE SIMULTANEOUS DETERMINATION OF PH AND REDOX POTENTIAL

A significant upgrading of a recently introduced biosensor system, cal led potentiometric alternating biosensor is presented. The transducer consists of a light-addressable silicon chip, which provides regions p roperly modified and functionalized to yield sensitivity to either pH or redox potentials. The computer controlled system drives an array of light sources, allowing two-dimensional signal acquisition and proces sing. The system can provide multiparameter information related to the local modifications made on the sensing surface of the transducer. Th is work presents a detailed description of the measuring principles an d the spatial resolution obtainable with the system. In addition, the complete circuit design is presented, both for signal conditioning, an d for the bidimensional matrix addressing. A typical experiment for se lective measurements is presented. (C) 1995 American Institute of Phys ics.