Self-assembled sulfonated β-Cyclodextrin layer on gold electrode for the selective electroanalysis of dopamine

Gold electrode with self-assembled D,L-cysteine grafted β-cyclodextrin sulfonic acid (Cys-β-CD∼SO3) layer was fabricated and used to investigate the electrochemical behavior of dopamine. The experimental results indicated that the self-assembled Cys-β-CD∼SO3 layer modified gold electrode has selective electrochemical response to dopamine with high sensitivity and excellent tolerance of ascorbic acid, which is the most common accompanying component in biological samples. Dopamine could be accurately determined in the concentration range of 1–200 μM in the presence of ascorbic acid of 5 mM. The relative standard deviation of 1.9% (n = 5) was achieved at a dopamine concentration of 5 × 10−5 M. The proposed sensor was successfully applied to the determination of dopamine in human blood serum samples.