Reduced Graphene Oxide and Poly (phenylalanine) Composite Modified Electrode for the Electrochemical Determination of Vanillin

Abstract

A simple, low-cost, and stable electrochemical sensor for vanillin is reported based on a glassy carbon electrode (GCE) modified with poly (phenylalanine) and electrochemically reduced graphene oxide (ERGO) composite (poly (phenylalanine)/ERGO/GCE). The surface structure of the bare and modified electrodes was characterized by Fourier transform infrared and scanning electron microscopy. The electrochemical behavior of vanillin at phenylalanine)/ERGO/GCE) was also studied by CV. Poly (phenylalanine)/ERGO/GCE) exhibited high electrocatalytic activity for the electrochemical oxidation of vanillin due to the synergetic effects of poly (phenylalanine) and ERGO. From linear sweep voltammetry study, the electrode reaction of vanillin is adsorption-controlled process. Furthermore, several electrochemical parameters such as number of electrons transferred (n=2), number of protons transferred (H+ = 2), electron transfer coefficient (α = 0.66) and surface concentration of vanillin (Ґ = 0.32 nmol cm−2) were calculated. SWV was used for quantitative determination of vanillin at phenylalanine)/ERGO/GCE). Under optimum conditions, the oxidation peak current of vanillin increased linearly with its concentration in the range 0.25–120 µM with a low detection limit of 0.025 µM. The developed sensor was successfully applied for the determination of vanillin in food and soft drink samples.

Electrochemical determination of vitamin B6 in pharmaceutical and energy drink samples

“…Poly(phenylalanine) film was deposited on the surface of bare GCE and F-MWCNT/GCE by electrochemical polymerization of phenylalanine using 5 cycles of CV in the potential range −1.5 to 2.5 V at the scan rate of 0.05 V s −1 in 0.1 M phosphate buffer solution (pH 8) containing 2 mM phenylalanine monomer. The mechanism of electro-polymerization of phenylalanine was-already reported [40]. The cyclic voltammograms (CVs) for the electro-polymerization of phenylalanine are displayed in Figure 2.…”

Development of a Co3O4/rGO Modified Electrochemical Sensor for Highly Sensitive Riboflavin Detection

“…The plot of the logarithm of the peak current versus the logarithm of the scan rate ( v ) shown in Figure S3D yielded a linear equation: $${{{\rm log}I}_{pa}=1.1439{\rm log}v-1.1978;{R}^{2}=0.9933\ and}$$ $${{{\rm log}I}_{pc}=-0.9415{\rm log}v+0.7260;{{\rm R}}^{2}=0.9973}$$ . The slope is approximately 1, indicating an adsorption‐controlled electrode reaction [11b,13d] . The plot of oxidation peak potential versus logarithm of scan rate (graph not shown) yielded a linear equation; $${{E}_{pa}=0.0202{\rm log}v-0.04535;\ {R}^{2}=0.9621.$…”

“…Table 2 shows the exchange current density ($${{J}_{o}}$$ ) and electron transfer rate constant ( k o ) for the nanocomposite‐modified electrode are significantly higher than those for the bare electrode estimated using [Eq. (3,4)] [13d] . This enhancement is attributed to the high active surface area of the nanocomposite electrode and the electrostatic interactions between the functional groups on the electrode surface and RF. $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {J}_{o}={{RT}\over{n{R}_{ct}AF}}\hfill\cr}}$$$ $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {R}_{ct}={{RT}\over{{n}^{2}{F}^{2}AC{k}^{o}}}\hfill\cr}}$$$ …”

Simple Fabrication of Mesoporous Praseodymium Cerate via an Eco-Friendly Route for Development of Carbendazim Electrochemical Sensor

“…Chemical sensors' repeatability and detection limit have been significantly improved by the use of nanomaterials for selective analyte determination. [32][33][34][35][36][37] Lanthanide ions have large atomic magnetic moments and strong spin-orbit coupling as well as an abundance of coordination modes because of their particular 4 f electron configurations. 38 These ion complexes have special magnetic, electrical, and optical characteristics, which is why lanthanide nanoparticles have recently received a lot of attention.…”