Sol–gel derived metal dispersed ceramic–graphite composite electrode for amperometric determination of dopamine Original Research Article

A new silver dispersed composite electrode made of sol–gel derived ceramic–graphite has been demonstrated for the determination of dopamine. Silver has been immobilized within the porous and rigid silicate network in the composite by the specific interaction with (3-mercaptopropyl)trimethoxysilane (MPS). The modified composite electrode coated with Nafion exhibited good catalytic activity for the oxidation of dopamine at a reduced potential of 0.35 V with good sensitivity and selectivity. The sensor showed a linear response to dopamine in the concentration range from 6.6×10−6 to 1.2×10−3 M with a correlation coefficient of 0.9987. The electrode surface can be easily renewed by a simple mechanical polishing and has the advantages of good reproducibility, rapid response and remarkable stability.