Voltammetric determination of TBHQ at a glassy carbon electrode surface activated by in situ chemical oxidation

Abstract

In this article, a bare glassy carbon electrode (GCE) surface was directly activated by a simple in situ chemical method, which was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Based on these results, it was found that oxygen-containing functional groups at the modified GCE surface were enhanced with a low damage to the surface state. Hence, the modified GCE exhibited an excellent performance, such as the negatively charged surface, good reproducibility and high selectivity. The resulting electrode was applied as a sensitive sensor for detection of antioxidant tertiary butyl hydroquinone (TBHQ), and a good linear relationship was obtained between the oxidation peak current and the concentration in a broad range of 1.0 μM-1.1 mM, with detection limits of 67 nM (S/N = 3) by DPV. Electrochemical parameters of TBHQ on the resulting GCE were also investigated, suggesting that the modified GCE could promote electron transfer kinetics towards the electrochemical reaction of TBHQ. Besides, the present method was used for determination of TBHQ in jatropha biodiesel with recovery ranging from 95.2% to 103.2%.

Multi-walled carbon nanotubes: Size-dependent electrochemistry of phenolic compounds

“…On the other hand, the selection of more positive potentials at the region of plateau of current for all phenolic compounds, which is a common practice when a hydrodynamic method (under stirring or flow rate) with amperometric detection is used, revealed that the use of MWCNT-modified electrodes may not be essential for the determination of HQ, TBHQ, CT, and DP because the gain in sensitivity and linear range is not so significant (10 to 40%). The limit of detection values obtained under both amperometric conditions on the SD-MWCNT-modified GCE were estimated as 0.03 (for DP), 0.17 (for CT and HQ) and 0.33 mmol L À1 (for TBHQ), which are within the values verified by previous works using modified electrodes containing CNTs or composites formed by CNTs and other chemical modifiers applied for DP (0.015-1.76 mmol L À1 ) [37,38,[41][42][43][44][45], CT (0.095-2.0 mmol L À1 ) [39,40,[47][48][49][50], HQ (0.02-2.6 mmol L À1 ) [46][47][48][49][50], and TBHQ (0.067-5.0 mmol L À1 ) [51][52][53][54].…”

Improved Electrochemiluminescence Behavior of Glassy Carbon Electrode Through In Situ Chemical Bonding Modification

“…However, those treatments only got the poor oxidation rates because glassy carbon has an extreme inertness to resist chemical attack. Fortunately, the in situ chemical oxidized GCE possesses a desirable oxidation rates and affinity behavior to cationic or quinines . Therefore, the negatively charged surface of GCE ox resulted by large amount of oxygen‐containing functional groups is significant to the attraction and bonding behavior of GCE ox .…”

“…Prior to oxidation, the bare GCE was polished with 0.3 μm and 0.05 μm alumina powders subsequently, and then successively sonicated in 1 : 1 (v/v) HNO 3 ‐water solution, 1 : 1 (v/v) ethanol‐water solution and double distilled water for several minutes. Then the preparation of GCE ox was based on our previously developed method, which is similar to the preparation method of graphene oxide established by Hummers and Offeman ,. The surface of GCE ox would contain ‐CHO, −COOH and −OH etc.…”

“…However, the extreme surface stability makes glassy carbon difficult to be in situ chemical modified. With the widely application of glassy carbon electrode (GCE) in electrochemical analysis, researchers found that the surface pretreatments such as heating, laser activation, electrochemical oxidation,, and chemical oxidation, etc., could make the surface of GCE strongly adsorb the analytes and activate the anodic oxidation of analytes such as catecholamines and ascorbic acid. Undergoing these pretreatments, especially with the chemical oxidation pretreatment, a larger effective surface area is achieved, the fresh carbon sites are exposed and oxygen containing groups are produced on the surface of GCE.…”

“…Undergoing these pretreatments, especially with the chemical oxidation pretreatment, a larger effective surface area is achieved, the fresh carbon sites are exposed and oxygen containing groups are produced on the surface of GCE. The oxidized GCE surface has an improved electron transfer rate or adsorptive behavior for some electroactive analytes . Based on the reported works, the chemically inert surface of GCE is speculated to be activated by the oxygen containing groups, which makes it probable to be in situ bonded with the specific molecules, such as ruthenium complexes, and to overcome the drawbacks of the traditional modification methods …”