Performance Of Boron-doped Diamond Electrode Research Articles

Biofouling and performance of boron-doped diamond electrodes for detection of dopamine and serotonin in neuron cultivation media

Boron doped diamond has been considered as a fouling-resistive electrode material for in vitro and in vivo detection of neurotransmitters. In this study, its performance in electrochemical detection of dopamine and serotonin in neuron cultivation media Neurobasal™ before and after cultivation of rat neurons was investigated. For differential pulse voltammetry the limits of detection in neat Neurobasal™ medium of 2 µM and 0.2 µM for dopamine and serotonin, respectively, were achieved on the polished surface, which is comparable with physiological values. On oxidized surface twofold higher values, but increased repeatabilities of the signals were obtained. However, in Neurobasal™ media with peptides-containing supplements necessary for cell cultivation, the voltammograms were notably worse shaped due to biofouling, especially in the medium isolated after neuron growth. In these complex media, the amperometric detection mode at +0.75 V (vs. Ag/AgCl) allowed to detect portion-wise additions of dopamine and serotonin (as low as 1–2 µM), mimicking neurotransmitter release from vesicles despite the lower sensitivity in comparison with neat NeurobasalTM. The results indicate substantial differences in detection on boron doped diamond electrode in the presence and absence of proteins, and the necessity of studies in real media for successful implementation to neuron-electrode interfaces.

First electrochemical study of a potent antifungal drug caspofungin: Application to its enhanced voltammetric sensing based on the performance of boron-doped diamond electrode in CTAB-mediated measurements

This present study describes the first electrochemical investigation of caspofungin, which is a semisynthetic echinocandin class of antifungal drug. For this purpose, an electrochemically pretreated (anodically and subsequently cathodically) boron-doped diamond (BDD) electrode was used. The cyclic voltammetric scans showed a single oxidation step that is irreversible and controlled by a dual mechanism of adsorption and diffusion. For the optimization of experimental conditions, the influence of the electrode pretreatment, pH of the supporting electrolyte, concentration of cationic surfactant cetyltrimethylammonium bromide (CTAB), accumulation variables, and instrumental parameters was examined on the current response of caspofungin. The improved sensitivity of the voltammetric measurements was observed due to the synergistic effect of CTAB on the adsorption capacity of BDD electrode in alkaline pH conditions. Employing square-wave adsorptive stripping voltammetry (using open-circuit accumulation for 60 s), the oxidation signal at around +0.45 V allowed to the determination of caspofungin in Britton-Robinson buffer at pH 11.0 containing 1 × 10−4 M CTAB. The process could be used in the concentration range from 2.06 × 10−7 to 1.03 × 10−5 M (from 0.25 to 12.5 μg mL−1 as acetate salt) with a detection limit of 5.27 × 10−8 M (0.064 μg mL−1 as acetate salt). A technique developed here was used successfully to determine caspofungin concentration in commercial parenteral dosage formulations.

Electrochemical and analytical performance of boron-doped diamond electrode for determination of ascorbic acid

AbstractThe electrochemical behavior and determination of ascorbic acid (AA) was investigated at a bare boron-doped diamond (BDD) electrode using cyclic and differential pulse voltammetry. The influence of pH of supporting electrolyte and scan rate on the current response of analyte was examined to select the suitable experimental conditions. It was found that AA provided one well-shaped irreversible and diffusioncontrolled oxidation peak at +0.87 V vs. Ag/AgCl in Britton-Robinson buffer pH 4.0. Applying differential pulse voltammetry, the peak current of AA was linearly proportional to its concentration from 5 × 10-6to 2 × 10-4mol L-1(R2= 0.999), with the limit of detection of 1.1 × 10-6mol L-1and the good repeatability (relative standard deviation of 2.3 %). The developed electroanalytical protocol was successfully applied to determine the content of AA in commercial pharmaceutical preparations, based on the standard additions method, with the obtained recovery of 122 %. The accomplished analytical performance indicates that BDD electrodes are promising electrochemical sensors for pharmaceutical analysis.

The Performance of Boron‐Doped Diamond Electrode for the Determination of Ramipril and its Association with Hydrochlorothiazide

AbstractThe voltammetric behavior of ramipril (RMP), an angiotensin‐converting enzyme inhibitor, was investigated for the first time in the literature on a boron‐doped diamond electrode (BDDE) using cyclic (CV) and square‐wave voltammetry (SWV). Its behavior was also considered in the presence of a thiazide diuretic, hydrochlorothiazide (HCTZ), for the simultaneous determination. The performance of BDDE and glassy carbon electrode (GCE) was compared, since RMP provides a high oxidation potential. It was observed that the anodic peak potentials for HCTZ and RMP at the BDDE were 1.23 and 1.67 V (vs. Ag/AgCl (3.0 mol L‐1 KCl)) by CV in BR buffer solution (pH 2.0), respectively. The influence of supporting electrolyte, pH and scan rate in the current response of these both drugs was examined to select optimum experimental conditions. By this way, the determination of RMP and its association with HCTZ using SWV and a BDDE was successfully applied in real samples (single and combined dosage forms), with results in close agreement at 95% confidence level with those obtained using high‐performance liquid chromatography.

Improved electrochemical performance of boron-doped diamond electrode depending on the structure of titanium substrate

Abstract This work is focused on the role of porous titanium (Ti) substrate on the electrochemical performance of boron-doped diamond (BDD) films. BDD film deposited on porous Ti substrate combines the excellent property of porous Ti and BDD film, porous Ti endows the film three-dimensional (3D) porous performance and enhances the surface area of BDD electrode. The effective electrochemical surface area of 3D-Ti/BDD electrode is 8.37 cm 2 cm − 2 , 3.2 times as much as that of conventional plate BDD electrode while smaller electron transfer resistance (31.3 Ω cm 2 ) for Fe(CN) 6 3 − /Fe(CN) 6 4 − redox couple on 3D-Ti/BDD electrode is obtained compared to 128.3 Ω cm 2 . 3D-Ti/BDD electrode presents higher response current and the degradation of aspirin reveals that corresponding kinetic constant for plate and 3D-Ti/BDD electrode is 0.185 h − 1 and 0.367 h − 1 , respectively. Moreover, porous BDD electrode owns higher stability analyzing by accelerated life tests, 25% higher than plate BDD electrode. The enhancement of electrocatalytic activity and stability is essentially attributed to porous structure of Ti substrate.

Electrochemical performance of boron-doped diamond electrode in surfactant-containing media for ambroxol determination

A novel application of boron-doped diamond electrode is introduced for the determination of ambroxol, a potential antioxidant drug belonging to the expectorant class. The electrochemical oxidation of ambroxol was first investigated by cyclic voltammetry using boron-doped diamond and glassy carbon electrodes in aqueous solutions both with and without the addition of surfactant. The compound was irreversibly oxidized in one/two steps at high positive potentials, resulting in the formation of a couple with a reduction and re-oxidation wave at less positive potentials. Special attention was given to the use of adsorptive stripping voltammetry at a surface of mildly oxidized boron-doped diamond electrode in aqueous solutions over the pH range of 1.0–10.0. Addition of anionic surfactant (sodium dodecylsulfate) to ambroxol-containing electrolyte enhanced the stripping current signal. Using square-wave stripping mode, the drug yielded a well-defined voltammetric response in phosphate buffer pH 2.5 containing 4×10−4M sodium dodecylsulfate at +1.02V (versus Ag/AgCl) (after 30s accumulation at +0.50V). The process could be used to determine ambroxol in the concentration range of 0.05–0.7μM, with a detection limit of 0.010μM (4.2ngmL−1). The suggested method was successfully applied to pharmaceuticals and spiked human urine samples.

Degradation of humic acid from water by advanced electrochemical oxidation method

In this study, the electrooxidation treatment method using boron-doped diamond (BDD) electrodes was investigated for the degradation of humic acid (HA) following absorbance at 254 nm (A254), color (A436) and total organic carbon (TOC) analysis. Also, a surrogate SUVA254 parameter was used to evaluate the aromatic carbon content. Prior to the application of the electrooxidation for HA degradation the electrochemical behavior of BDD electrode in HA containing 0.1M Na2SO4 supporting electrolyte was studied by cyclic voltammetry (CV), and the working conditions of bulk electrolysis corresponding to water decomposition potential range were selected. The influence of the applied current density, pH, HA initial concentration on the performance of BDD electrode was investigated in relation with the specific electrical consumption. Applying electrooxidation using BDD electrodes for the real surface water treatment led to the mineralization efficiency of 65% after 150 minutes.

Influence of boron concentration on growth characteristic and electro-catalytic performance of boron-doped diamond electrodes prepared by direct current plasma chemical vapor deposition

A series of boron-doped diamond (BDD) electrodes were prepared by direct current plasma chemical vapor deposition (DC-PCVD) with different compositions of CH4/H2/B(OCH3)3 gas mixture. A maximum growth rate of 0.65mgcm−2h−1 was obtained with CH4/H2/B(OCH3)3 radio of 4/190/10 and this growth condition was also a turning point for discharge plasma stability which arose from the addition of B(OCH3)3 that changed electron energy distribution and influenced the plasma reaction. The surface coating structure and electro-catalytic performance of the BDD electrodes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, Hall test, and electrochemical measurement and electro-catalytic oxidation in phenol solution. It is suggested that the boron doping level and the thermal stress in the films are the main factors affecting the electro-catalytic characteristics of the electrodes. Low boron doping level with CH4/H2/B(OCH3)3 ratio of 4/199/1 decreased the films electrical conductivity and its electro-catalytic activity. When the carrier concentration in the films reached around 1020cm−3 with CH4/H2/B(OCH3)3 ratio over a range of 4/195/5–4/185/15, the thermal stress in the films was the key reason that influenced the electro-catalytic activity of the electrodes for its effect on diamond lattice expansion. Therefore, the BDD electrode with modest CH4/H2/B(OCH3)3 ratio of 4/190/10 possessed the best phenol removal efficiency.

Essential Explanation of the Strong Mineralization Performance of Boron-Doped Diamond Electrodes

Electrochemical oxidation of p-nitrophenol was examined using differentanodic materials, including T/boron-doped diamond (BDD), Ti/SnO2-Sb/PbO2, and Ti/SnO2-Sb anodes. The results demonstrated that Ti/BDD anodes had a much stronger mineralization performance than the other two anodes. Furthermore, it was found that hydroxyl radicals could mainly exist as free hydroxyl radicals at BDD anodes, which could react with organic compounds effectively. This implied that the dominant mechanism for a much higher mineralization capacity of BDD anodes would be attributed to the existence of free hydroxyl radicals in the BDD anode cell rather than adsorbed hydroxyl radicals on the BDD anode. To further corroborate this hypothesis, electrochemical oxidation of p-substituted phenols (p-nitrophenol, p-hydroxybenzaldehyde, phenol, p-cresol, and p-methoxyphenol) was examined at the Ti/BDD, Ti/SnO2-Sb/ PbO2, and Ti/SnO2-Sb anodes, respectively. The study revealed that for Ti/BDD electrodes, the degradation rate of p-substituted phenols (k) increased with the increase of Hammett's constant (sigma), which confirmed the dominance of free hydroxyl radicals at BDD anodes and its effective reaction with organics therein. For Ti/SnO2-Sb/PbO2 electrodes, the degradation rate of p-substituted phenols (k) increased with the increase of initial surface concentration gamma (representing the adsorption capacity of phenols to electrode surface), which indicated that organic compounds mainly reacted with adsorbed hydroxyl radicals at PbO2 anodes. For Ti/SnO2-Sb electrodes, however, k increased with the increase of the integrated parameter S (representing the effects of both sigma and gamma), which implied that organic compounds reacted with both adsorbed hydroxyl radicals and free hydroxyl radicals at SnO2 anodes.