Abstract

Bulk modification of carbon paste electrode (CPE) with graphene oxide nanoribbon and 3-(4 '-amino-3 '-hydroxy-biphenyl-4-yl) -acrylic acid (3,4 '-AA-GONR/CPE) was used to develop a new electro-chemical sensor for sensitive determination of droxidopa and carbidopa at physiological pH. Chronoamperometry, differential pulse voltammetry, and cyclic voltammetry were employed to evaluate electro-chemical responses of as-prepared modified electrodes. A linear dependence of oxidation peak current on the concentration of droxidopa within a range between 0.02 and 300.0 mu M was also observed with determination limit of 10.0 nM (S/N = 3). Desirable reproducibility, stability, and selectivity were seen in as-prepared 3,4 '-AA-GONR/CPE, implying hopeful uses for concurrent detection of droxidopa and carbidopa.