Voltammetric determination of tannic acid in beverages using pencil graphite electrode

Abstract

Vu D.L., Ertek B., Dilgin Y., Červenka L. (2015): Voltammetric determination of tannic acid in beverages using pencil graphite electrode. Czech J. Food Sci., 33: 72-76.The pretreated pencil graphite electrode (Pre-PGE) prepared by a chronoamperometry technique was applied for the determination of tannic acid using anodic stripping differential pulse voltammetry. The currents obtained from voltammetry measurements at optimum conditions were linearly correlated with the concentration of tannic acid. Calibration curve was obtained for tannic acid in the concentration range of 5.0-500 × 10 -9 mol/l. The limit of detection was found to be 1.5 × 10 -9 mol/l. The content of tannic acid in beverage samples determined with Pre-PGE was in good agreement with that obtained by the standard spectrophotometric method.

Sensitive Voltammetric Determination of Natural Flavonoid Quercetin on a Disposable Graphite Lead

“…With increasing pH, oxygen-containing groups in pencil lead were deprotonized and anionic forms of quercetin (QHand Q 2-) (13) were formed, leading to repulsion of negatively charged quercetin from the negatively charged surface. The same mechanism of interaction between tannic acid and the pretreated pencil graphite electrode was described in our previous study (37).…”

“…Pretreated pencil graphite electrodes were prepared by a chronoamperometric technique described in our previous study (37). The surface of pencil graphite electrode was pretreated by applying a potential of 1.45 V for 60 s in the supporting electrolyte (0.1 mol/L of phosphate buffer solution containing 0.1 mol/L of KCl, pH=7.0).…”

“…Quercetin is well known for its use as a redox mediator in carbon-based electrodes to enhance the electrocatalytic oxidation of some organic compounds such as dopamine (31), tyramine (32) or NADH (33) (34)(35)(36)(37). In this paper, we describe a simple and rapid method for the determination of quercetin using a pretreated pencil graphite electrode.…”

Pencil Graphite Electrodes: A Versatile Tool in Electroanalysis

“…PGEs were pretreated potentiostatically by maintaining the electrode in an electrolyte for more than 30 s at a selected potential higher than 1.3 V [ 9 , 53 , 55 , 56 , 60 , 70 , 99 – 101 , 105 , 192 , 193 ] or by scanning the potential at a given scan rate, for a certain number of cycles within a large potential range [ 2 , 57 , 58 , 61 , 69 , 103 , 106 , 188 , 194 ]. Some papers report a comparison between the two mentioned activation procedures and depending on the electrochemical performances obtained for the investigated analyte one of them was selected; for example, chronoamperometric activation of PGE was used for alkylphenols [ 50 ] and tannic acid [ 51 ] analysis and cyclic voltammetric activation of PGE for dopamine [ 21 ] and bisphenol A [ 54 ] detection. A precharged PGE developed by charging the electrode surface using CV in a NaOH solution was applied to phenols sampling and determination [ 104 ].…”

Voltammetric determination of aluminium(III) at tannic acid capped-gold nanoparticle modified electrodes

“…Next, AuNPs@TA were electrochemically characterized by cyclic voltammetry in HCl-KCl solution at pH1.0, revealing an oxidation peak at a potential of 0.31 V vs SCE (Figure 3a, blue curve), attributed to the oxidation of TA [48] as illustrated in equation 1. For this purpose, a GCE was modified by drop casting ca 5.7 x 10 8 AuNPs@TA, corresponding to a surface concentration of nanoparticles of approximately one monolayer.…”