Abstract
The present work reports a study of the electrocatalytic activity of CeO2 nanoparticles and gold sononanoparticles (AuSNPs)/CeO2 nanocomposite, deposited on the surface of a Sonogel-Carbon (SNGC) matrix used as supporting electrode and the application of the sensing devices built with them to the determination of ascorbic acid (AA) used as a benchmark analyte. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to investigate the electrocatalytic behavior of CeO2- and AuSNPs/CeO2-modified SNGC electrodes, utilizing different concentrations of CeO2 nanoparticles and different AuSNPs:CeO2 w/w ratios. The best detection and quantification limits, obtained for CeO2 (10.0 mg·mL−1)- and AuSNPs/CeO2 (3.25% w/w)-modified SNGC electrodes, were 1.59 × 10−6 and 5.32 × 10−6 M, and 2.93 × 10−6 and 9.77 × 10−6 M, respectively, with reproducibility values of 5.78% and 6.24%, respectively, for a linear concentration range from 1.5 μM to 4.0 mM of AA. The electrochemical devices were tested for the determination of AA in commercial apple juice for babies. The results were compared with those obtained by applying high performance liquid chromatography (HPLC) as a reference method. Recovery errors below 5% were obtained in most cases, with standard deviations lower than 3% for all the modified SNGC electrodes. Bare, CeO2- and AuSNPs/CeO2-modified SNGC electrodes were structurally characterized using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). AuSNPs and AuSNPs/CeO2 nanocomposite were characterized by UV-vis spectroscopy and X-ray diffraction (XRD), and information about their size distribution and shape was obtained by transmission electron microscopy (TEM;. The advantages of employing CeO2 nanoparticles and AuSNPs/CeO2 nanocomposite in SNGC supporting material are also described. This research suggests that the modified electrode can be a very promising voltammetric sensor for the determination of electroactive species of interest in real samples.
Highlights
Due to their chemical and physical properties, nanomaterials, and in particular nanoparticles, are the subject of intensive research nowadays because of their scientific and technological importance.gold nanoparticles (AuNPs) are employed in many fields: biosensors, cosmetics, nanoelectronic, catalysis, semiconductors, and biomedicine, among others [1,2,3,4,5]
AuSNPs and AuSNPS/CeO2 nanoparticles were characterized by X-Ray Diffraction (XRD) and information about their size distribution and shape was obtained using the Transmission Electron Microscopy (TEM) technique
As it can be clearly seen in Figure 1(A), AuSNPs are spherical-shaped and well dispersed from each other, with almost no aggregates
Summary
Due to their chemical and physical properties, nanomaterials, and in particular nanoparticles, are the subject of intensive research nowadays because of their scientific and technological importance. Some analytes determined by using CeO2-nanostructured-modified electrodes are: uric acid [24], ascorbic acid (AA) [25] and their mixture [12] at modified glassy carbon electrodes, dopamine [26] at a based carbon fiber microbiosensor, and urea [27] at an indium tin oxide (ITO)-coated glass substrate Their analytical applications are not much extended despite of the good selectivity, sensitivity, reproducibility and stability obtained for many of these devices, what make them promising voltammetric sensors for real sample analysis. The present work reports the study of the electrocatalytic activity of CeO2 nanoparticles and AuSNPs/CeO2 nanocomposites Both kinds of nanomaterials were deposited on the surface of a Sonogel-Carbon (SNGC) matrix by a simple drop-casting method and the sensing devices built with them were applied to the determination of AA, used as benchmark analyte. AuSNPs and AuSNPs/CeO2 nanocomposite were characterized by UV-vis spectroscopy, X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM)
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