Abstract
A novel sensor of cysteine self-assembled monolayers over gold nanoparticles modified gold electrode has been constructed for the determination of epinephrine in presence of sodium dodecyl sulfate (Au/Au-nano-Cys...SDS). Electrochemical investigation and characterization of the modified electrode are achieved using cyclic voltammetry, linear sweep voltammetry, and scanning electron microscopy. The Au/Au-nano-Cys...SDS electrode current signal is remarkably stable via repeated cycles and long term stability, due to the strong Au-S bond, compared to the Au/Au-nano electrode. The catalytic oxidation peak currents obtained from linear sweep voltammetry (LSV) increased linearly with increasing epinephrine concentrations in the range of 2 to 30 mu mol L-1 and 35 to 200 mu mol L-1 with correlation coefficients of 0.9981 and 0.9999 and a limit of detection of 0.294 nmol L-1 and 1.49 nmol L-1, respectively. The results showed that Au/Au-nano-Cys...SDS can selectively determine epinephrine in the coexistence of a large amount of uric acid and glucose. In addition, a highly selective and simultaneous determination of tertiary mixture of ascorbic acid, epinephrine, and acetaminophen is explored at this modified electrode. Excellent recovery results were obtained for determination of epinephrine in spiked urine samples at the modified electrode. Au/Au-nano-Cys...SDS can be used as a sensor with excellent reproducibility, sensitivity, and long term stability.