Analytical Application of Pyramidal, Rodlike, and Spherical Gold Nanostructures: Simultaneous Detection of Ascorbic Acid and Uric Acid

Abstract

Simultaneous detection of ascorbic (AA) and uric acid (UA) is developed at pyramidal (NP), rodlike (NR), and spherical (NS) gold nanostructures, due to their high electrocatalytic activities toward the oxidation of AA and UA. Unlike at bare gold electrode, the fouling resulted from the oxidized product of AA is eliminated at the nanostructured gold electrode. The voltammetric signals of AA and UA are completely separated with a potential difference of 216 mV, 158 mV and 195 mV, respectively, at the pyramidal, rodlike, and spherical gold surfaces. The experimental results reveal that solution pH effects the peak separation of AA and UA, acidic solution is more favorable for the simultaneous determination of AA and UA than neutral one, than alkaline one. The coexistence of a large excess of AA does not interfere with the voltammetric sensing of UA, vice versa. All the three kinds of nanostructured gold electrodes show excellent sensitivity, stability, selectivity, low detection limit, quick response and wide linear range in the repeated detection of AA and UA. The practical utility of the present nanostructured gold electrodes is demonstrating by determining the concentration of AA in fruit juice and UA in urine sample.

Simultaneous determination of dopamine and uric acid using a glassy carbon paste electrode modified with copper- para red complex

“…of electrochemical systems for the detection of ascorbic acid (AA), dopamine (DA) and uric acid (UA) in human urine samples and blood serum have gotten extensive consideration in the literature [1][2][3][4]. AA is an exceptionally basic electroactive biological molecule, which is extremely outstanding to prevent scurvy, and is crucial to keep up great immune response and help wound healing [5].…”

“…Figure 8. Cyclic voltammograms of DA and UA concentration (from a to q) (4,8,12,16,20,30,40,50,60,80,100,120,160,200, 300, 400, 600 µmol L -1 ) in the presence of AA at modified Cu/PR/GCP electrode in pH 7.0 PBS at scan rate of 100 mVs -1 Figure 9. Anodic peak currents vs. DA concentration (µmol L -1 ) at optimum condition…”

Electrochemical Formation of Nanostructured Gold Surfaces on Glassy Carbon for the Determination of Dopamine

“…Several methods have been used to prepare gold surfaces with high surface area, including: hard templating of SiO 2 spheres , chemical dealloying , H 2 bubble formation , and electrochemical deposit , The latter one appears to be a fast and low cost method to fabricate well‐defined nanostructured surfaces . Metal nanoparticles in the shape of spheres, rods, triangles and hierarchical flower‐like structures, as well as dendritic‐like deposits have been prepared under such an approach . Nevertheless, the use of organic additives in solution or previously adsorbed is a common strategy to control the growth of the nanostructured phase, affecting the interfacial chemistry of the final material .…”

Electrochemical Molecular Imprinted Sensors Based on Electrospun Nanofiber and Determination of Ascorbic Acid

“…[19][20][21][22][23] In our previous work, the simultaneous detection of AA and UA was developed with nanostructured gold, due to their high electrocatalytic activities toward the oxidation of AA and UA. 24 In this work, we investigated the possibility of preparing electrospun nanofibers that contain molecularly imprinted binding sites. The cellulose acetate (CA)/multi-walled carbon nanotubes (MWCNTs)/polyvinylpyrrolidone (PVP)-based nanofiber membranes were fabricated by electrospinning technique.…”