In order to find the most suitable immobilization protocol, a comparison of three strategies based on the application of -NH2 and -COOH functionalized supports with the different activation agents (glutaraldehyde and carbodiimide) have been conducted for the covalent enzyme (laccase) attachment. Two kinds of the supports, namely mesoporous silica (SBA-15, MCM-41) and carbonaceous (glassy carbon, graphite) powders, have been used.
It was found that a biosensor consisted of tubular detector of silver solid amalgam as a working electrode and the enzymatic mini-reactor with laccase covalently attached to glutaraldehyde activated -NH2 functionalized MCM-41 shows the best results regarding sensitivity and stability for dopamine detection.