Use Of Boron-doped Diamond Electrode Research Articles

Recent advances of boron-doped diamond electrochemical sensors toward environmental applications

The electrocatalytic properties of boron-doped diamond (BDD) electrodes have been considered for a variety of sensing applications. The unusual electrochemical properties of BDD include a large potential window, a small background current, and better resistance to fouling than other carbon-based electrodes. The use of BDD for remediation and environmental sensing applications has recently attracted the interest of the sensor research community. This review focuses on recent developments that involve the use of BDD as an environmentally friendly sensing material for environmental analysis. The electrochemical properties of boron-doped diamond that has undergone surface modification (e.g., with metals or enzymes) will be considered. Recent achievements involving the use of BDD electrodes for detecting pesticides, mycotoxins, peroxides, and phenolic compounds are considered.

Electrochemical Ozone Generation Using Compacted High Pressure High Temperature Synthesized Boron Doped Diamond Microparticle Electrodes

Electrochemical ozone production (EOP) from water is an attractive, green technology for disinfection. Boron doped diamond (BDD) electrodes, grown by chemical vapor deposition (CVD), have been widely adopted for EOP due to their wide anodic window in water and excellent chemical and electrochemical stability. High pressure high temperature (HPHT) synthesis, an alternative growth technique used predominantly for the high-volume synthesis of nitrogen doped diamond microparticles, has been seldom employed for the production of conductive BDD electrodes. In this paper, we demonstrate, for the first time, the use of BDD electrodes fabricated from HPHT conductive BDD microparticles for EOP. The BDD microparticles are first compacted to produce freestanding solid electrodes and then laser micromachined to produce a perforated electrode. The compacted HPHT BDD microparticle electrodes are shown to exhibit high EOP, producing 2.23 ± 0.07 mg L−1 of ozone per ampere of current, at consistent levels for a continuous 20 h period with no drop off in performance. The HPHT electrodes also achieve a reasonable current efficiency of 23%, at a current density of 770 mA cm−2.

Electrochemical CO2 reduction on sub-microcrystalline boron-doped diamond electrodes

Boron-doped diamond (BDD) electrodes are being increasingly investigated for application to electrochemical CO2 reduction. Previous, studies have mainly focused on microcrystalline (MC) BDD electrodes. In our study, we present an analysis of electrochemical CO2 reduction using sub-microcrystalline (SMC) BDD electrodes with different boron doping concentrations (0.28%, 0.11% and 0.03%). Unlike the microcrystalline case, these synthetic SMC BDD films with high sp2-bonded carbon do not show a boron-concentration dependence in terms of the activity of CO2 reduction to form formic acid (HCOOH). All the electrodes enabled efficient CO2 reduction at close to the maximum Faradaic efficiency for HCOOH in the range of 70% to 80%. From our observations, it is suggested that the sp2-bonded carbon should be crucial for the CO2 reduction. The results are hoped to enable a relaxation on the restrictions on the use of BDD electrodes towards industrial CO2 reduction application.

Assessment of the use of boron-doped diamond electrode for highly sensitive voltammetric determination of the azo-dye carmoisine E−122 in food and environmental matrices

A new protocol for the analysis of the azo-dye carmoisine (CMS) is presented by coupling differential pulse voltammetry (DPV) with a cathodically pretreated boron-doped diamond electrode (CPT-BDDE), in phosphate buffer solution (pH 2.0). The CMS presented diffusion-controlled oxidation and reduction peaks at +0.88 and −0.15 V vs Ag/AgCl, respectively. The effect of the pretreatment conditions, pH, and supporting electrolytes were evaluated to the voltammetric determination of CMS. Under optimized conditions, the differential pulse voltammetric signals for CMS were linear over the concentration range of 0.059–1.31 μmol L−1 and 0.010–0.079 μmol L−1 with limits of detection of 7.0 and 3.0 nmol L−1, for the anodic and cathodic processes respectively. The method was precise for CMS determination (RSD < 5.0%) and selective against other dyes. The developed protocol was successfully applied in the analysis of CMS in surface water and foodstuffs with accurate results in comparison with those obtained using a validated spectrophotometric method.

Feasibility of the use of boron-doped diamond electrode coupled to electroanalytical techniques for the individual determination of pravastatin and its association with acetylsalicylic acid

In this work, we explored the efficiency of the use of the pretreated boron-doped diamond electrode (BDDE) coupled to electroanalytical techniques for the individual determination of pravastatin (PRAV) and its association with acetylsalicylic acid (ASA). The voltammetric behavior of PRAV and ASA was investigated by cyclic voltammetry showing irreversible and diffusion-controlled oxidation processes for both analytes, regardless of the type of BDDE pretreatment. Under the optimized conditions (cathodically pretreated BDDE and phosphate buffer solution, pH 4.0), the analytical response for PRAV was linear over the range from 1.0 to 30 μmol L−1 for individual determination using amperometry, obtaining a limit of detection (LOD) of 0.102 μmol L−1. For simultaneous determination of PRAV and ASA, (using the anodically pretreated BDDE in 0.3 mol L−1 H2SO4 solution), the responses were linear over the range of 1.08–16.4 μmol L−1 for PRAV and 3.96–42.75 μmol L−1 for ASA using SWV, obtaining a LOD of 0.204 and 0.078 μmol L−1, respectively. The methods were successfully applied to pharmaceutical formulations, synthetic urine and tap water samples.

The Use of Boron-Doped Diamond Electrode for the Determination of Selected Biocides in Water Samples

In recent years, the remains of chemical substances in water environments, referred to as emerging organic contaminations, have been more and more often studied by analysts. This work shows the possibility of using a boron-doped diamond electrode to determine low concentration levels of remains of pharmaceuticals in environmental samples. The study focused on selected biocides from the group of azole fungicides (itraconazole and posaconazole) and was performed using quick and sensitive electrochemical methods. The cyclic voltammetry method was used in order to determine the properties of these compounds, whereas analytical characterization was performed using square wave voltammetry. The work involved the specification of the optimum electrooxidation conditions of the selected fungicides, their comparative characterization, and the development of a new, sensitive methods of itraconazole and posaconazole assay. The proposed procedures allowed us to determine itraconazole in the range from 7.9 × 10−8 to 1.2 × 10−6 moL·L−1 and posaconazole in the range from 5.7 × 10−8 to 8.44 × 10−7 moL·L−1. The relative standard deviation of the measurements did not exceed 5.85%. The developed procedures were successfully used to determine itraconazole and posaconazole concentration in water samples and the assay recovery was between 93.5% and 102.8%.

Boron Doped Diamond Electrodes in Flow-Based Systems.

Boron-doped diamond (BDD) electrodes present several notable properties, such as the largest potential window of all electrode materials (especially in anodic potentials), low background and capacitive currents, reduced fouling compared to other electrodes, mechanical robustness, and good stability over time. On the other hand, flow-based systems are known as well-established approaches to minimize reagent consumption and waste generation and with good compromise between sample throughput and analytical performance (mechanization of chemical assays). This review focuses on the use of BDD electrodes for electrochemical detection in flow systems, such as flow injection analysis (FIA), batch injection analysis (BIA), high performance liquid chromatography (HPLC), and capillary electrophoresis (CE). The discussion deals with the historical evolution of BDD, types of electrochemical pre-treatments (cathodically/H-terminated or anodically/O-terminated), cell configurations, and analytical performance. Articles are discussed in chronological order and subdivided according to the type of flow system: FIA, BIA, HPLC, and CE.

Dual use of boron-doped diamond electrode in antibiotics-containing water treatment and process control

Abstract This study aimed to investigate the dual role of boron-doped diamond (BDD) electrode and electrooxidation process in the electrochemical degradation of tetracycline (TC) – as model of antibiotics considered emergent pollutants in water – and also in the electrochemical detection based process control. Cyclic voltammetry (CV) was used to determine the operating parameters for both TC degradation/mineralization and its electrochemical detection in the process control. The operating parameters such as current density, pH and TC concentration range were set to achieve the best process performance. The mechanism and kinetics of TC electrodegradation are also discussed. A current density of 50 Am−2 and pH 5 were found to be optimum for TC degradation and mineralization in a concentration range between 25 and 100 mg L−1. Furthermore, these conditions enhanced the biodegradability character of TC during a subsequent biological treatment step in a wastewater treatment plant (WWTP). The versatility of the BDD electrode also made possibile for it to be used for the electrochemical detection of TC using CV, allowing the process control with the same electrode, hence confirming the dual role of the electrode material.

The Use of Boron-doped Diamond Electrode on Yeast-based Microbial Fuel Cell for Electricity Production

The dependency of fossil energy in Indonesia caused the crude oil production to be drastically decreased since 2001, while energy consumption increased. In addition, The use of fossil energy can cause several environmental problems. Therefore, we need an alternative environment-friendly energy as solution for these problems. A microbial fuel cell is one of the prospective alternative source of an environment-friendly energy source to be developed. In this study, Boron-doped diamond electrode was used as working electrode and Candida fukuyamaensis as biocatalyst in microbial fuel cell. Different pH of anode compartment (pH 6.5-7.5) and mediator concentration (10-100 μM) was used to produce an optimal electricity. MFC was operated for 3 hours. During operation, the current and voltage density was measured with potensiostat. The maximum power and current density are 425,82 mW/m2 and 440 mA/m2, respectively, for MFC using pH 7.5 at anode compartment without addition of methylene blue. The addition of redox mediator is lowering the produced electricity because of its anti microbial properties that can kill the microbe.

A portable electrochemical method for cocaine quantification and rapid screening of common adulterants in seized samples

A simple and robust batch-injection analysis system with square-wave voltammetric (BIA-SWV) detection is proposed for the determination of cocaine and screening of the most common adulterants (benzocaine, caffeine, lidocaine, phenacetin, paracetamol, and procaine) in seized cocaine samples. The sample only requires a dissolution step in electrolyte (0.1molL−1H2SO4) prior injection into the BIA cell. SWV scanning is performed after injection of the sample plug and cocaine and adulterants are electrochemically oxidized on a boron-doped diamond electrode (BDDE), resulting in a unique voltammetric profile. The use of BDDE was essential to achieve, for the first time, the electrochemical oxidation of cocaine in an acid medium. Using the optimized experimental conditions, a linear response was found for cocaine concentrations ranging from 6 to 30mgL−1, with a detection limit of 0.27mgL−1 (0.89μmolL−1). The accuracy of the proposed method was estimated by comparing the results obtained for seized cocaine samples by GC-FID and with the addition and recovery protocol. Furthermore, BIA with multiple pulse amperometric (MPA) detection is also proposed as a promising protocol for faster screening of seized cocaine samples.

Electrochemical inactivation of cyanobacteria and microcystin degradation using a boron-doped diamond anode — A potential tool for cyanobacterial bloom control

Cyanobacterial blooms are global phenomena that can occur in calm and nutrient-rich (eutrophic) fresh and marine waters. Human exposure to cyanobacteria and their biologically active products is possible during water sports and various water activities, or by ingestion of contaminated water. Although the vast majority of harmful cyanobacterial products are confined to the interior of the cells, these are eventually released into the surrounding water following natural or artificially induced cell death. Electrochemical oxidation has been used here to damage cyanobacteria to halt their proliferation, and for microcystin degradation under in-vitro conditions. Partially spent Jaworski growth medium with no addition of supporting electrolytes was used. Electrochemical treatment resulted in the cyanobacterial loss of cell-buoyancy regulation, cell proliferation arrest, and eventual cell death. Microcystin degradation was studied separately in two basic modes of treatment: batch-wise flow, and constant flow, for electrolytic-cell exposure. Batch-wise exposure simulates treatment under environmental conditions, while constant flow is more appropriate for the study of boron-doped diamond electrode efficacy under laboratory conditions. The effectiveness of microcystin degradation was established using high-performance liquid chromatography–photodiode array detector analysis, while the biological activities of the products were estimated using a colorimetric protein phosphatase-1 inhibition assay. The results indicate potential for the application of electro-oxidation methods for the control of bloom events by taking advantage of specific intrinsic ecological characteristics of bloom-forming cyanobacteria. The applicability of the use of boron-doped diamond electrodes in remediation of water exposed to cyanobacteria bloom events is discussed.

Oxidação Eletroquímica de Anlodipino e Hidroclorotiazida Sobre o Eletrodo de Diamante Dopado com Boro: Potencialidade de Determinação Simultânea em Urina

The present study was undertaken to evaluate the use of boron-doped diamond electrode in the simultaneous voltammetric determination of antihypertensives amlodipine and hydrochlorothiazide in urine sample. Two very well-resolved and reproducible oxidation peaks of amlodipine and hydrochlorothiazide, with separation of 0.360 V, were obtained in Britton-Robinson buffer (pH 5.0). Under the optimum analytical experimental conditions, the square-wave voltammetric method exhibited linear responses for simultaneous determination of amlodipine and hydrochlorothiazide in the concentration range 1.0 × 10 −7 – 2.1 × 10 −6 mol L −1 and 2.0 × 10 −6 – 2.2 × 10 −5 mol L −1 , with detection limits of 5.6 × 10 −8 mol L −1 and 1.6 × 10 −7 mol L −1 , respectively. The proposed method was applied in the simultaneous determination of amlodipine and hydrochlorothiazide in urine sample . DOI: http://dx.doi.org/10.17807/orbital.v7i1.673

Use of boron-doped diamond electrode pre-treated cathodically for the determination of trace metals in honey by differential pulse voltammetry

In this work, a methodology for the determination of Cu(II), Pb(II), Cd(II) and Zn(II) in honey by differential pulse anodic stripping voltammetry (DPASV) on a nano crystalline boron-doped diamond electrode (BDD) is proposed. A 33 Box-Behnken Design, 32 Factorial Design and Principal Components Analysis (PCA) were performed to optimise the electrochemical conditions. According to the response surfaces obtained, it was stipulated for Zn analysis a pH of 4, Ed of −1.50 V and td of 240 s. For simultaneous analysis of Cu, Pb and Cd a pH of 1, Ed of −0.95 V and td of 240 s was used. Detection limits of 0.37, 0.40, 1.28 and 0.16 μg L−1 were found for Cu, Pb, Cd and Zn, respectively. The analyte concentration ranged between 0.242 and 1.38 mg L−1 for Cu, 0.129 and 0.918 mg L−1 for Pb and 0.819 and 2.492 mg L−1 for Zn, while no significant concentrations were found during Cd analyses. The honey samples were also analysed by Hg-coated glassy carbon electrode and graphite furnace atomic absorption spectrometry (GF AAS) through non-parametric ANOVA and no evidence of significant differences among the results was observed within a 95% confidence interval.

Development of electrochemical biosensors by e-beam lithography for medical diagnostics

In this work the fabrication and characterization of boron-doped diamond (BDD) nanoelectrode arrays are discussed. The use of boron-doped diamond electrodes is very attractive due to advantageous properties including high reproducibility, stability, and robustness under extreme conditions, where conventional electrode materials may undergo severe erosion. BDD electrodes have also proved to be very useful because they show an extremely wide potential window in aqueous solutions without oxidation of the electrode itself. This allows electrochemical detection, at tiny background currents, of a number of substances that oxidize at very positive potentials, where other electrodic materials are not suitable. BDD based NEAs were prepared using Si substrates coated with a layer of Boron doped diamond as macroelectrode. NEAs were obtained by creating an array of nanoholes by electron beam lithography (EBL) in a thin film of polycarbonate deposited on top of the macroelectrode. This approach leads to the formation of recessed nanoelectrodes. The parameters for using polycarbonate as a novel electron beam resist have been optimized and successfully used for fabrication of NEAs. The most interesting properties of this polymer for nanofabrication purposes are the high lithographic contrast, which allows the creation of structures of dimensions less than 100nm; chemical stability, which guarantees a long-term use in electrochemical solutions and the possibility of functionalization with biological molecules (DNA and proteins). NEAs have been characterized with cyclic voltammetry and have provided voltammetric signals controlled by pure radial diffusion. The low background current of BDD added to the properties of NEAs indicate that this system can be applied for the development of sensors with high sensitivity. Polycarbonate surface of NEAs was successfully functionalized with small ss-DNA sequence, confirming the possibility of exploiting these systems as diagnostic biosensors.

CE with a boron‐doped diamond electrode for trace detection of endocrine disruptors in water samples

Off-line SPE and CE coupled with electrochemical detection have been used for the determination of bisphenol A (BPA), bisphenol F, 4-ethylphenol, and bisphenol A diglycidyl ether in bottled drinking water. The use of boron-doped diamond electrode as an electrochemical detector in amperometric mode that provides a favorable analytical performance for detecting these endocrine-disrupting compounds, such as lower noise levels, higher peak resolution with enhanced sensitivity, and improved resistance against electrode passivation. The oxidative electrochemical detection of the endocrine-disrupting compounds was accomplished by boron-doped diamond electrode poised at +1.4 V versus Ag/AgCl without electrode pretreatment. An off-line SPE procedure (Bond Elut® C18 SPE cartridge) was utilized to extract and preconcentrate the compounds prior to separation and detection. The minimum concentration detectable for all four compounds ranged from 0.01 to 0.06 μM, having S/N equal to three. After exposing the plastic bottle water container under sunlight for 7 days, the estimated concentration of BPA in the bottled drinking water was estimated to be 0.03 μM. This proposed approach has great potential for rapid and effective determination of BPA content present in water packaging of plastic bottles that have been exposed to sunlight for an extended period of time.

Electrosynthesis of ferrates with diamond anodes

AbstractThis work is focused on the electrosynthesis of ferrates with boron‐doped diamond (BDD) anodes. These compounds are oxo‐anions of Fe(V) and Fe(VI) with a very high oxidant potential over a wide range of pHs, and with a great variety of industrial and environmental applications. It has been observed that the use of BDD electrodes can improve the results obtained by steel electrodes in the synthesis of ferrates. However, the results seem to be limited by the availability of oxidizable iron species in the reagent solution. The production yield is revealed to be strongly dependent on the iron raw material, hydroxyl anions concentration, temperature, and current density. The use of iron‐powder bed as iron‐raw material increases the availability of oxidizable‐iron species and therefore allows improving the efficiency of the electrosynthesis with BDD. Likewise, current densities over 1000 A m−2 and temperatures around 25°C guaranty high current efficiencies and ferrates concentrations. © 2008 American Institute of Chemical Engineers AIChE J, 2008

Electrochemical synthesis of peroxomonophosphate using boron-doped diamond anodes

A new method for the synthesis of peroxomonophosphate, based on the use of boron-doped diamond electrodes, is described. The amount of oxidant electrogenerated depends on the characteristics of the supporting media (pH and solute concentration) and on the operating conditions (temperature and current density). Results show that the pH, between values of 1 and 5, does not influence either the electrosynthesis of peroxomonophosphate or the chemical stability of the oxidant generated. Conversely, low temperatures are required during the electrosynthesis process to minimize the thermal decomposition of peroxomonophosphate and to guarantee significant oxidant concentration. In addition, a marked influence of both the current density and the initial substrate is observed. This observation can be explained in terms of the contribution of hydroxyl radicals in the oxidation mechanisms that occur on diamond surfaces. In the assays carried out below the water oxidation potential, the generation of hydroxyl radicals did not take place. In these cases, peroxomonophosphate generation occurs through a direct electron transfer and, therefore, at these low current densities lower concentrations are obtained. On the other hand, at higher potentials both direct and hydroxyl radical-mediated mechanisms contribute to the oxidant generation and the process is more efficient. In the same way, the contribution of hydroxyl radicals may also help to explain the significant influence of the substrate concentration. Thus, the coexistence of both phosphate and hydroxyl radicals is required to ensure the generation of significant amounts of peroxomonophosphoric acid.

Evaluation of boron doped diamond electrodes for organic electrosynthesis on a preparative scale⋆

We have investigated some anodic and cathodic transformations using boron doped diamond (BDD) electrodes. The oxidation of a propargylic alcohol as well as the aromatic side chain oxidation in water as electrolyte did not␣yield the desired products in high yield and selectivity and led mainly to the formation of CO2 due to␣electrochemical incineration of the starting material. With methanol as electrolyte, however, the reactivity of BDD electrodes is similar to graphite in most anodic methoxylation reactions, but the inactive behaviour of BDD electrodes leads to a different reaction pathway possibly involving methoxyl radicals with charge transfer from the electrolyte. It has been found that at BDD anodes benzylic single and double bonds can be split yielding aromatic acetals and esters. With phenanthrenes as starting material, o,o′-disubstituted biaryls were obtained. So the use of BDD electrodes provides an efficient and environmentally friendly access to this interesting class of compounds. The high H2 overpotential of BDD cathodes enables smooth and selective reduction of functional groups like oximes. Due to the high chemical and mechanical stability of the diamond layer of today’s electrodes, electrode lifetime as well as reproducibility of the electrosyntheses has improved markedly. Aqueous basic conditions, however, must be avoided for BDD anodes. These conditions result in degradation of the diamond surface.

Electrochemical Synthesis of Peroxodiphosphate Using Boron-Doped Diamond Anodes

Peroxodiphosphate salts are strong oxidizing agents that presently can be used as reagents in organics synthesis, cosmetic, agriculture, polluted water treatment, and also as bleaching agents in the detergent industry. They also have potential uses as persulfates substitutes. In this work, a new method for the synthesis of peroxodiphosphate, based on the use of boron-doped diamond electrodes, is described. The procedure developed is able to produce high-purity peroxodiphosphate (no reagents different from phosphate salts are used as raw materials) with a high current efficiency. The efficiencies of the process strongly depend on the pH and on the operating conditions (temperature and current density). The optimum range of pH is 12-13. Current densities over , and low temperatures, guarantee high current efficiencies and product conversions. The pH control is considered to be one of the more important operation constraints in the process. Great concentrations of phosphate in the raw materials increase the process efficiencies but they also seem to favor the corrosion of the electrode. Concentrations below of are recommended to avoid this problem.

Voltammetric determination of L-cysteine at conductive diamond electrodes.

Boron-doped diamond (BDD) electrodes were used to examine L-cysteine (CySH) oxidation in alkaline media. The results of the voltammetric and polarization measurements showed that at BDD electrodes the overall CySH oxidation reaction is controlled by the initial electrochemical step, i.e., the oxidation of the CyS- electroactive species. The same conclusion was supported by the results of a study of pH effects. Conversely, at glassy carbon (GC) electrodes, the same reaction is controlled by the desorption of the reaction products. These results account for the poor response for CySH determination at GC compared to BDD. It was found that BDD exhibits excellent behavior for CySH determination, clearly outperforming GC. The results demonstrate that measurement of the peak current for CySH oxidation can be used as a basis for simple method for determining CySH in the micromolar concentration range by the use of BDD electrodes.