3.1.2. CHIT and glutaraldehyde amount
In the immobilization procedure, glutaraldehyde was used as a bifunctional reagent to provide cross-linkages between the amino groups on both matrix and the biomolecules. It is also known that these interactions are pH dependent and the most efficient binding
yield between proteins and amino groups of CHIT matrix was reported to be 7.0–7.5. Hence pH 7.5 was used for the enzyme immobilization [36–38]. In order to check the effect of CHIT and glutaraldehyde amounts on AG/PyOx/CHIT biosensor, different concentrations
of CHIT and glutaraldehyde solutions were tested. Fig. 2 depicts the effect of CHIT (A) and glutaraldehyde (B) amount on the biosensor response. Maximum response was obtained when 1.0% of CHIT and glutaraldehyde concentrations were used. As can be seen in
the figure, further increments caused lower signals due to the possible diffusion problems as a result of higher crosslinkage amounts.