| 초록 |
A novel and selective enzymatic biosensor was designed and constructed for voltammetric determination of levodopa (l-Dopa) in aqueous media (phosphate buffer solution, pH=7). Biosensor development was on the basis of to physically immobilizing of horse radish peroxidase (HRP) as electrochemical catalyst by sol-gel on glassy carbon electrode modified with organic nucleophilic carbon nanotube composite which in this composite p-phenylenediamine (pPDA) as organic nucleophile chemically bonded with functionalized MWCNT (MWCNT-COOH). The results of this study suggest that prepared bioorganic nucleophilic carbon nanotube composite (HRP/MWCNT-pPDA) shows fast electron transfer rate for electro oxidation of l-Dopa because of its high electrochemical catalytic activity toward the oxidation of l-Dopa, more ?NH 2 reactive sites and large effective surface area. Also in this work we measured l-Dopa in the presence of folic acid and uric acid as interferences. The proposed biosensor was characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), FT-IR spectroscopy and cyclic voltammetry (CV). The differential pulse voltammetry (DPV) was used for determination of l-Dopa from 0.1 mu;M to 1.9 mu;M with a low detection limit of 40nM (for S/N=3) and sensitivity was about 35.5 mu;A/ mu;M. Also this biosensor has several advantages such as rapid response, high stability and reproducibility. |
