| The objective of the research was to examine the feasibility of utilizing optical redox sensors as an alternative to electronic redox sensors. The research investigated two dyes, phenosafranin (3,7-diamino-5-phenylphenazinium chloride) and thionin (3,7-diamino-5-phenothiazinium acetate), that change their optical properties as redox potential changes. The dyes were immobilized in a Nafion film and were attached to the distal end of a fiber optic cable. As the redox condition of the bulk solution was changed, measurements of the dyes' absorbance and fluorescence were taken. The results indicated that phenosafranin immobilized in commercial Nafion membrane is a suitable redox indicator. Optical readings of the absorbance peaks correspond to ORP meter values signifying that changes in redox conditions can be observed optically. The long term project goal is to create an in-situ redox sensor that could assess redox conditions in the field. |
