Electrochemical selective detection of dopamine on microbial carbohydrate-doped multiwall carbon nanotube-modified electrodes

Microbial carbohydrate-doped multiwall carbon nanotube (MWNT)-modified electrodes were prepared for the purpose of determining if 4-(2-aminoethyl)benzene-1,2-diol (3,4-dihydroxyphenylalanine; dopamine) exists in the presence of 0.5 mM ascorbic acid, a representative interfering agent in neurotransmitter detection. The microbial carbohydrate dopants were α-cyclosophorohexadecaose (α-C16) from Xanthomonas oryzae and cyclic-(1 → 2)-β-d-glucan (Cys) from Rhizobium meliloti. The cyclic voltammetric responses showed that the highest sensitivity (5.8 × 10−3 mA cm−2 μM−1) is attained with the Cys-doped MWNT-modified ultra-trace carbon electrode, and that the α-C16-doped MWNT-modified glassy carbon electrode displays the best selectivity to dopamine (the approximate peak potential separation is 310 mV).