Optically transparent agarose membranes can be easily prepared
and simply activated by epichlorohydrine. The chemical
immobilization of Congo Red on the epoxy-activated membrane
resulted in a sensitive pH optical sensor for low pH values.
The membrane showed a good sensitivity with a reasonable
response time, good reproducibility and long term stability, with
no evidence of the dye leakage. The proposed method can be
identically used for preparation of a number of immobilized
agarose-based optical sensors by the simple activation method.
Further work will be directed for the immobilization of other
indicators on the activated-agarose membranes and study of their
applications as optical sensors