Unmodified Boron-doped Diamond Research Articles

Electrochemical Detection of the Antidiabetic Medication Metformin in Human Urine and Pharmaceutical Tablets Using Boron-Doped Diamond Electrode

Electrochemical Detection of the Antidiabetic Medication Metformin in Human Urine and Pharmaceutical Tablets Using Boron-Doped Diamond Electrode

Development of an environmentally friendly method for the determination of prednisolone in natural waters using unmodified boron-doped diamond electrode

Development of an environmentally friendly method for the determination of prednisolone in natural waters using unmodified boron-doped diamond electrode

The cathodically pretreated boron-doped diamond electrode as an environmentally friendly electrochemical tool for the detection and monitoring of mesotrione in food samples

Excessive pesticide use can harm human health, making it essential to develop new techniques to monitor hazardous pesticides in food. Our study focuses on detecting mesotrione (MST) using an unmodified boron-doped diamond (BDD) electrode. This was the first application of cathodically pretreated BDD electrode for the detection of MST, based on its oxidation at a high potential value of +1.4 V. We theoretically examined the oxidation mechanism of MST trough the utilization of density functional theory (DFT) methodology. The utilized DPV method achieved a detection limit of 0.45 μM and showed satisfactory selectivity. The practical application of this method was demonstrated by examining corn-based food products. To ensure practical application of the method, MST was deliberately added to the samples to evaluate the accuracy of the proposed method. The effectiveness of the method was confirmed by using HPLC method. This environmentally-friendly approach can establish a solid foundation for future use in food analysis.

Designing Molecularly Imprinted Polymer-Modified Boron-Doped Diamond Electrodes for Highly Selective Electrochemical Drug Sensors.

Drug detection in biological solutions is essential in studying the pharmacokinetics of the body. Electrochemical detection is an accurate and rapid method, but measuring multiple drugs that react at similar potentials is challenging. Herein, we developed an electrochemical sensor using a boron-doped diamond (BDD) electrode modified with a molecularly imprinted polymer (MIP) to provide specificity in drug sensing. The MIP is a polymer material designed to recognize and capture template molecules, enabling the selective detection of target molecules. In this study, we selected the anticancer drug doxorubicin (DOX) as the template molecule. In the electrochemical measurements using an unmodified BDD, the DOX reduction was observed at approximately -0.5 V (vs Ag/AgCl). Other drugs, i.e., mitomycin C or clonazepam (CZP), also underwent a reduction reaction at a similar potential to that of DOX, when using the unmodified BDD, which rendered the accurate quantification of DOX in a mixture challenging. Similar measurements conducted in PBS using the MIP-BDD only resulted in a DOX reduction current, with no reduction reaction observed in the presence of mitomycin C and CZP. These results suggest that the MIP, whose template molecule is DOX, inhibits the reduction of other drugs on the electrode surface. Selective DOX measurement using the MIP-BDD was also possible in human plasma, and the respective limits of detection of DOX in PBS and human plasma were 32.10 and 16.61 nM. The MIP-BDD was durable for use in six repeated measurements, and MIP-BDD may be applicable as an electrochemical sensor for application in therapeutic drug monitoring.

A simple and reliable electrochemical method employing an unmodified boron-doped diamond electrode for the determination of triclocarban

Since the advent of the COVID-19 pandemic, triclocarban-containing cleaning products have been increasingly consumed. As triclocarban is an emerging compound, it is necessary to develop new sensors for its monitoring. So, a simple and reliable electroanalytical method for the determination of triclocarban using an unmodified boron-doped diamond electrode was developed. The application of a cathodic pretreatment (−2.0 V, 30 min, 0.5 mol L−1 H2SO4) on the electrode surface provided higher current intensities and lower resistance to charge transfer in contrast to the non-treated surface. On the diamond electrode surface, the triclocarban showed an irreversible behavior with two oxidation peaks at +1.10 and +1.40 V vs. Ag/AgCl, KCl(sat). The hypothesis for removing hydrogens of both amide groups of the triclocarban structure was supported by computational methodology which also explained the broadened oxidation peaks and the distance between them. The calibration curve for triclocarban, obtained by using differential pulse voltammetry in a supporting electrolyte composed of McIlvaine buffer (pH 3.0) and ethanol (80:20 v/v), covered a concentration range of 1.0 to 50 μmol L−1, and it exhibited a detection limit of 0.31 μmol L−1 under optimized experimental conditions. Using an accumulation time of 120 s at open circuit potential, a calibration curve by differential pulse adsorptive stripping voltammetry was constructed in a range of 0.05 to 20 µmol L−1 of triclocarban, with a detection limit of 18 nmol L−1. Triclocarban quantification assays were carried out on samples of antibacterial soaps and river water, and data were recorded with acceptable precision and accuracy.

An Electrochemical Sensor of Theophylline on a Boron-Doped Diamond Electrode Modified with Nickel Nanoparticles.

Theophylline is a drug with a narrow therapeutic range. Electrochemical sensors are a potentially effective method for detecting theophylline concentration to prevent toxicity. In this work, a simple modification of a boron-doped diamond electrode using nickel nanoparticles was successfully performed for a theophylline electrochemical sensor. The modified electrode was characterized using a scanning electron microscope and X-ray photoelectron spectroscopy. Square wave voltammetry and cyclic voltammetry methods were used to study the electrochemical behavior of theophylline. The modified nickel nanoparticles on the boron-doped diamond electrode exhibited an electrochemically active surface area of 0.0081 cm2, which is larger than the unmodified boron-doped diamond's area of 0.0011 cm2. This modified electrode demonstrated a low limit of detection of 2.79 µM within the linear concentration range from 30 to 100 µM. Moreover, the modified boron-doped diamond electrode also showed selective properties against D-glucose, ammonium sulfate, and urea. In the real sample analysis using artificial urine, the boron-doped diamond electrode with nickel nanoparticle modifications achieved a %recovery of 105.10%, with a good precision of less than 5%. The results of this work indicate that the developed method using nickel nanoparticles on a boron-doped diamond electrode is promising for the determination of theophylline.

Quantification of ferulic acid using square-wave voltammetric method at an unmodified boron-doped diamond electrode

Quantification of ferulic acid using square-wave voltammetric method at an unmodified boron-doped diamond electrode

A strategy for low-cost portable monitoring of plasma drug concentrations using a sustainable boron-doped-diamond chip

On-site monitoring of plasma drug concentrations is required for effective therapies. Recently developed handy biosensors are not yet popular owing to insufficient evaluation of accuracy on clinical samples and the necessity of complicated costly fabrication processes. Here, we approached these bottlenecks via a strategy involving engineeringly unmodified boron-doped diamond (BDD), a sustainable electrochemical material. A sensing system based on a ∼1 cm2 BDD chip, when analysing rat plasma spiked with a molecular-targeting anticancer drug, pazopanib, detected clinically relevant concentrations. The response was stable in 60 sequential measurements on the same chip. In a clinical study, data obtained with a BDD chip were consistent with liquid chromatography–mass spectrometry results. Finally, the portable system with a palm-sized sensor containing the chip analysed ∼40 μL of whole blood from dosed rats within ∼10 min. This approach with the ‘reusable’ sensor may improve point-of-monitoring systems and personalised medicine while reducing medical costs.

Utilizing epicatechin voltammetric oxidation signal for the estimation of total phenolic content in the tea samples via the unmodified boron-doped diamond electrode surface

In this work, the boron-doped diamond (BDD) electrode surface was employed for the first time in conjunction with the epicatechin (EC) oxidation signal to estimate the total phenolic content of tea samples by voltammetry. During cyclic voltammetry analysis of the EC, an easily identifiable, irreversible, and adsorption-controlled oxidation peak was observed at around +1.05 V (vs. Ag/AgCl) in HNO3 solution. Our experimental setup was fine-tuned by investigating the effect of electrode pretreatment, pH of the supporting electrolyte, accumulation factors, and instrumental parameters on the oxidation peak response of EC. When measuring EC in a 0.1 mol L−1 HNO3 solution at +1.0 V, square-wave adsorptive stripping voltammetry provided a highly linear response (at open-circuit accumulation for 30 s). The dynamic range was determined to be between 1.0 and 50.0 μg mL−1 (3.4510−6–1.7210−4 mol L−1), while the detection limit was found to be 0.28 μg mL−1 (9.6510−7 mol L−1). Selectivity studies were performed with other phenolic compounds found in tea such as epigallocatechin gallate, catechin, tannic acid, and gallic acid. Finally, by assessing the total phenolic content in the black and green tea samples, the suggested approach's applicability was shown by providing an estimate of the EC equivalents present in the samples.

A simple and fast flow injection amperometry for the determination of methimazole in pharmaceutical preparations using an unmodified boron-doped diamond electrode.

In this work, an automated flow injection analysis (FIA) connected to a boron-doped diamond electrode (BDDE) was originally developed for the analysis of methimazole in pharmaceutical preparations. At a modification-free BDDE, methimazole was easilly oxidized. For the analysis of the mechanisms occurring at the electrode surface, cyclic voltammetry was employed to evaluate the impact of fundamental experimental parameters, such as pH and scan rate, on the BDDE response. For the quantitative detection, the FIA amperometric approach was constructed and used as a fast and sensitive method. The suggested approach provided a broad linear range of 0.5-50 μmol/L and a low detection limit of 10 nmol/L (signal-to-noise ratio = 3). Furthermore, the BDDE was successfully utilized to quantify methimazole in genuine samples from a variety of medicines, and its performance remained steady after more than 50 tests. The findings of amperometric measurements exhibit excellent repeatability, with relative standard deviations of less than 3.9 and 4.7 % for intra-day and inter-day, respectively. The findings indicated that, compared with traditional approaches, the suggested method has the following advantages: quick analysis time, simplicity, highly sensitive output, and no need for complicated operational processes.

The first electrochemical evaluation and voltammetric detection of the insecticide emamectin benzoate using an unmodified boron-doped diamond electrode

This study introduces for the first time an electroanalytical investigation and novel voltammetric method for the determination of emamectin benzoate (EB) using a cathodically pretreated boron-doped diamond electrode (CTP-BDDE). The CPT-BDDE electrode exhibited a well-defined irreversible signal at ∼1.35 V (vs. Ag/AgCl) using cyclic voltammetry. Different scan rates (from 10 to 750 mV s−1) suggested that the oxidation of EB on the BDDE surface is a diffusion-controlled process. Using square wave voltammetry, the anodic peak current was linear with EB concentrations from 0.25 mg L-1 to 12.5 mg L-1, with LOD and LOQ found to be 0.079 and 0.263 mg L-1, respectively. The effect of other insecticides used to treat sea lice and inorganic ions found in seawater on the voltammetric detection of EB was negligible. The proposed method was successfully applied to the determination of EB at different concentrations in real sea water samples. To the best of our knowledge, the voltammetric behaviour of EB and the electrochemical method for EB determination is reported for the first time.

An unmodified boron-doped diamond electrode for electroanalytical investigation and sensitive voltammetric quantification of antiviral drug famciclovir in the pharmaceutical formulation and serum samples

The current study offers an electroanalytical investigation and a novel voltammetric approach for the quantitative analysis of famciclovir (FCV) utilizing an unmodified boron-doped diamond (BDD) electrode. An irreversible, well-defined, diffusion-controlled anodic peak was observed at approximately +1.27 V (vs. Ag/AgCl) in acetate buffer solution (ABS, 0.1 mol L−1, pH 4.7) when the agent was tested using cyclic voltammetry. The voltammetric signals of the oxidation peaks are pH dependent (ranging from 2.0 to 7.0). Using square-wave mode, a good linear response was obtained for FCV quantification in 0.1 mol L−1 ABS (pH 4.7) solution at +1.26 V (vs. Ag/AgCl). Wide dynamic range was found for 0.1 to 50.0 μg mL−1 (3.11 × 10−7-1.56 × 10−4 mol L−1), with a low detection limit of 0.029 μg mL−1 (9.02 × 10−8 mol L−1). Applicability of the proposed method for the determination of FCV was demonstrated in the pharmaceutical formulation and model serum samples.

Electrooxidation of tetracycline antibiotic demeclocycline at unmodified boron-doped diamond electrode and its enhancement determination in surfactant-containing media

In this paper, for the first time, the study of voltammetric determination of tetracycline antibiotic demeclocycline was conducted. The oxidation of compound was investigated using a commercially available boron-doped diamond electrode pretreated electrochemically (anodic and subsequent cathodic). Addition of anionic surfactant, sodium dodecylsulfate (SDS) and cationic surfactant, cetyltrimethylammonium bromide (CTAB) to the demeclocycline-containing electrolyte solution at pH 2.0 and 9.0, respectively, was found to improve the sensitivity of the stripping voltammetric measurements. Employing square-wave stripping mode (after 30 s accumulation at open-circuit condition) in Britton-Robinson buffer, the limits of detection were found to be 1.17 μg mL−1 (2.3 × 10−6 M) for 4 × 10−4 SDS-containing buffer solution at pH 2, and 0.24 μg mL−1 (4.8 × 10−7 M) for 1 × 10−4 CTAB-containing buffer solution at pH 9.0. The feasibility of the developed approach for the quantification of demeclocycline was tested in urine samples.

Square-Wave Adsorptive Stripping Voltammetric Determination of Hesperidin Using a Boron-Doped Diamond Electrode

In the present study, an electroanalytical method for the determination of hesperidin using adsorptive stripping voltammetry at an unmodified boron-doped diamond (BDD) electrode is presented. In cyclic voltammetry, the compound showed one irreversible and adsorption-controlled oxidation peak, resulting in the formation of a couple with a reduction and re-oxidation wave at less positive potentials. Using square-wave stripping mode, the observed anodic peak current in 0.1 M perchloric acid solution at +0.90 V (vs. Ag/AgCl) (after 30 s accumulations at a fixed potential of +0.4 V) increased linearly from 2.5 to 70 μg/mL (4.09 × 10–6–1.15 × 10–4 M). A detection limit of 0.7 μg/mL (1.2 × 10–6 M) and relative standard deviation of 8.2% for the concentration of 2.5 µg/mL (n = 10) were observed. To evaluate the practical applicability of the BDD electrode, it was used for the quantification of hesperidin in the commercial dietary supplement formulations.

Improving the CO2 electrochemical reduction to formic acid using iridium-oxide-modified boron-doped diamond electrodes

Modification of iridium on the surface of boron-doped diamond (BDD) electrode has been performed to decrease the overpotential reduction of carbon dioxide (CO2) and produce value-added carbon compounds. The modification was performed using the cyclic voltammetry (CV) technique that successfully deposited iridium oxide on the surface of the BDD electrode with an Ir-to-C ratio of approximately 1:100. When the modified BDD electrode was utilized for CV of a dissolved-CO2-saturated solution, hydrogen evolution occurred at a potential of approximately −1.2 V (vs. Ag/AgCl), which was lower than that when an unmodified BDD was used. Furthermore, when this electrode was utilized for amperometry of the same solution at −1.7 V for 1 h, formic acid (HCOOH) was produced with a Faradaic efficiency of approximately 50%. Results indicated that the modified electrode has considerable potential for application to CO2 electrochemical reduction.

Development and application of electrochemical sensor of boron-doped diamond (BDD) modified by drop casting with tin hexacyanoferrate

This work presents the development and characterization of an electrochemical sensor of tin hexacyanoferrate (SnHCF), produced from the modification by drop casting of the boron-doped diamond electrode (BDD), and its subsequent evaluation in the determination of dopamine (DP) in a synthetic saliva sample. The sensors, BDD-SnHCF and unmodified BDD, were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy, where the BDD-SnHCF presented higher roughness and lower resistance to electronic transfer. Raman spectroscopy and energy-dispersive X-ray spectroscopy (EDS) were used to confirm the chemical composition and bonding of the SnHCF film. The electroactive area and the heterogeneous electron transfer rate constant (k0) presented higher values for BDD-SnHCF. Analytical curves were constructed, by batch injection analysis (BIA) with amperometric detection (BIA-AMP), and the slope obtained for BDD-SnHCF was significantly higher when compared with unmodified BDD. The detection limit for BDD-SnHCF (0.21 μmol L−1) presented a value sevenfold lower than unmodified BDD and good analytical frequency (72 h−1) obtained for the modified electrode. The determination of DP in saliva, as a proof-of-concept, achieved an excellent accuracy, reported by a recovery of (90% ± 8) in the sample. The results showed that SnHCF is an interesting alternative for the BDD drop casting modification, presenting a significant improvement in the electrochemical characteristics and analytical performance of DP in the determination by BIA-AMP compared with unmodified BDD.

Determination of Pb(II) and Cu(II) in microemulsified biodiesel using boron-doped diamond electrode

This study describes an electrochemical alternative to quantify metals in biodiesel, since this matrix present a complex structure. This methodology use square wave anodic stripping voltammetry (SWASV) associated with an unmodified boron-doped diamond (BDD) electrode to determine Pb(II) and Cu(II) in microemulsified biodiesel. The procedure was applied in samples of biodiesel from corn oil, allowing finding a LOD of 2.70 × 10−8 and 4.00 × 10−9 mol L−1 for Pb(II) and Cu(II), respectively, with satisfactory recovery values (95.8 – 118.1%) which are comparable with other convetional analysis described in the literature.

Simultaneous Monitoring of Febuxostat and Uric Acid in Human Serum Samples Using the Direct Square-Wave Voltammetric Method

Background: High uric acid serum level, hyperuricemia, is now associated with many diseases such as gout, chronic kidney disease, hypertension, coronary artery disease and diabetes. Febuxostat is a novel selective xanthine oxidase inhibitor approved for the treatment of hyperuricemia. Objective: The aim of this study was to develop a first analytical method for the simultaneous determination of febuxostat and uric acid. Methods: An unmodified boron-doped diamond electrode provided concurrent quantitation of drug at low levels and uric acid, which has clinical significance in the diagnosis and therapy of hyperuricemia, at relatively high concentrations. The direct square-wave voltammetric method was applied to the analysis of both analytes in human serum samples. Results: Under the optimized conditions, the linear response of peak current on febuxostat concentration was achieved in the range from 7.5 × 10-7 to 3 × 10-5 M, while uric acid showed two linear ranges of 5 × 10-6 - 5 × 10-5 M and 5 × 10-5 - 2 × 10-4 M. The method was successfully utilised for quantification of both analytes in human serum samples. Good recoveries were obtained without interference from common inorganic cations and anions as well as glucose, dopamine, ascorbic and folic acids at concentrations expected in physiological conditions. Conclusion: The great benefits of developed method are fast analysis (only 7.5 s for run), low cost and simplicity of performance.

Application of unmodified boron-doped diamond electrode for determination of dopamine and paracetamol

For the first time the application of unmodified boron doped diamond electrode for dopamine (DA) and paracetamol (PA) determination in biological samples and pharmaceutical preparations with the use of differential pulse voltammetry was demonstrated in the present work. The wide linear range of calibration graphs: from 1 × 10−7 to 2 × 10−4 mol L−1 for DA and PA, and very low detection limits were achieved, equaling 1.87 × 10−8 mol L−1 for DA and 1.35 × 10−8 mol L−1 for PA. The proposed sensor was successfully applied for determination of dopamine in urine samples, paracetamol in syrups for children, and for simultaneous determination of paracetamol and dopamine in blood and serum samples.

Analytical Approach for Detection of Ergosterol in Mushrooms Based on Modification Free Electrochemical Sensor in Organic Solvents

Ergosterol (Erg) is the major sterol component in the plasma membranes of fungi. The main goal of this work was to develop rapid, reliable, and cost-effective method toward Erg detection based on application of unmodified boron-doped diamond electrode. Several organic solvents were tested (acetonitrile, dimethyformamide, dimethylsulfoxide, dichloromethane), and it was found that best analytical characteristics were achieved using acetonitrile containing 0.1 M tetrabutylammonium hexa-fluorophosphate as supporting electrolyte. Oval shaped and well-defined oxidation peak was recorded at potential of around 1.17 V versus Ag/Ag+ non-aqueous reference electrode. Under optimized experimental conditions, linear working range from 2 to 200 μM was estimated, with limit of detection of 0.7 μM, using square wave voltammetry. Negligible effect of possible interfering compound was observed. Proposed methodology was successfully applied for estimation of Erg content in mushrooms extract with satisfactory results in comparison with spectrophotometric procedure. Obtained results clearly show that developed analytical methodology can be adequate replacement for the, up to date, used methods and open-novel approach for ergosterol detection.