Au-IDA microelectrodes modified with Au-doped graphene oxide for the simultaneous determination of uric acid and ascorbic acid in urine samples

Abstract

An electrochemical sensor based on graphene oxide decorated with gold nanoparticles has been prepared for the simultaneous quantification of uric acid (UA) and ascorbic acid (AA) in urine samples. The gold interdigitated microelectrodes array (Au-IDA) has been modified using graphene oxide doped with gold nanoparticles (AuNPs-GO/Au-IDA), which was characterized by TEM, FE-SEM, XPS and cyclic voltammetry Excellent results were obtained for the separate quantification of UA and AA by chronoamperometry. The electrochemical sensor exhibits limits of detection (LODs) of 1.4 M and 0.62 M for AA and UA, respectively, limits of quantification (LOQs) of 4.6 M (AA) and 2.0 M (UA), and the working ranges obtained were between 4.6 M and 193 M for AA and between 2 M and 1.05 mM for UA. The repeatability was studied at 20 M providing coefficients of variation of 16 % for AA and 13 % for UA.Moreover UA does not interfere in the measurement of AA and viceversa (provided that the concentration of UA is equal to or higher than 450 M in the latter case). For lower concentrations of UA, an easy and fast strategy to quantify both analytes is presented.The good electrocatalytic activity achieved with this material makes it useful for the quantification of AA and UA in biological fluids. Other analytes like glucose, dopamine and epinephrine have been investigated. The results allow us to conclude that they do not interfere in the quantification of AA and UA in PBS (0.25 M, pH 7.0). Human urine samples have been analyzed using the method proposed, contaning AA and UA concentration levels of (0.588  0.002) mM and (1.43  0.02) mM, respectively, which are in the concentration range of these analytes in urine samples for healthy people.

Magnetic ionic liquid assisted single‐drop microextraction of ascorbic acid before its voltammetric determination

“…The electrochemical technique presented here was compared with those previously reported for the quantification of AA . As shown in Table , coupling differential pulse voltammetry with single‐drop microextraction resulted in considerably lower LOD as well as comparable width of linear range.…”

Electrochemically Reduced Graphene Oxide-Based Screen-Printed Electrodes for Total Tetracycline Determination by Adsorptive Transfer Stripping Differential Pulse Voltammetry

“…In summary, no significant changes were observed in TET quantitative recoveries (97% and 104%, 80 μM) in the presence of ascorbic acid and phenol, using a 1:10 TET/interference ratio. However, uric acid (at 500 μM as common concentration in urine samples) [31] yields an intense peak in both techniques (AdTDPV and DPV) (see Figure 6C). The strong absorption ability of uric acid on the ERGO-SPE surface proved to have a clear impact on the AdTDPV of the TETs (recovery 43% for 80 μM TET).…”

“…The strong absorption ability of uric acid on the ERGO-SPE surface proved to have a clear impact on the AdTDPV of the TETs (recovery 43% for 80 μM TET). Like TET, uric acid presents a π-electron resonance in its double ring and also However, uric acid (at 500 µM as common concentration in urine samples) [31] yields an intense peak in both techniques (AdTDPV and DPV) (see Figure 6C). The strong absorption ability of uric acid on the ERGO-SPE surface proved to have a clear impact on the AdTDPV of the TETs (recovery 43% for 80 µM TET).…”

The doping level of boron-doped diamond electrodes affects the voltammetric sensing of uric acid

“…The electrochemical properties of such electrodes are in general strongly inuenced by non-uniform doping in diamond, boundary effects, varied ratios of graphite to diamond (sp 3 /sp 2 ), surface morphology and termination. 26,27 According to the literature survey, [9][10][11][12][13][14]21,[28][29][30][31][32][33][34][35][36][37][38] the utilization of a GCE and CPE as a working electrode is dominant in the electrochemical determination of UA. Until now, the methodology using a pencil graphite electrode (PGE) modied with over-oxidized poly(3,4-ethylenedioxythiophene) nanobers has been considered to be the most sensitive with the lowest LOD of 0.001 mM.…”