Commercial Glassy Carbon Electrodes Research Articles

Simultaneous monitoring of amoxicillin and paracetamol in synthetic biological fluids using a 3D printed disposable electrode with a lab-made conductive filament.

In this work, we are pleased to present for the first time a 3D-printed electrochemical device using a lab-made conductive filament based on graphite (Gr) and polylactic acid (PLA) polymer matrix for the simultaneous detection of amoxicillin (AMX) and paracetamol (PAR). The sensor was properly characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). Compared to the commercial glassy carbon electrode (GCE), the superior performance of the 3D-Gr/PLA electrode was verified with a 3.8-fold more favored charge transfer. A differential pulse voltammetry (DPV) method was proposed providing a linear working range of 4 to 12 μmol L-1 for both analytes and a limit of detection (LOD) of 0.80 and 0.51 μmol L-1 for AMX and PAR, respectively. Additionally, repeatability studies (n = 5, RSD < 5.7%) indicated excellent precision, and recovery percentages ranging from 89 to 109% when applied to synthetic human urine, saliva, and plasma samples, attested to the accuracy of the method. The studies also indicate that the sensor does not suffer significant interference from common substances (antibiotics and biomarkers) present in the biological fluids, which makes it a promising analytical tool considering its low-cost, ease of manufacturing, robustness, and electrochemical performance.

V2O5-Fe3O4/rGO Ternary Nanocomposite with Dual Applications as a Dye Degradation Photocatalyst and OER Electrocatalyst.

The design and synthesis of structured nanomaterials with dual properties have always been highly attractive in various fields, especially in the reduction of environmental pollution as well as the generation of renewable energy. In this study, the synthesized ternary V2O5-Fe3O4/rGO nanocomposite was investigated to evaluate both the photocatalytic and electrocatalytic activities for the removal of methylene blue (MB) dye under UV/visible light radiation and oxygen evolution reaction (OER), respectively. The magnetized V2O5-Fe3O4/rGO nanocomposite is characterized by TEM, FE-SEM (with coupling by elemental mapping), EDS, XRD, FTIR, Raman, PL, DRS, and UV-vis analyses. The obtained results show that the graphene oxide substrate is decorated very well using Fe3O4 and V2O5 nanoparticles and converted to reduced graphene oxide (rGO). Furthermore, the V2O5-Fe3O4/rGO nanocomposite is considered as an active catalyst material to modify the commercial glassy carbon electrode for OER using linear sweep voltammetry (LSV). The photocatalytic activity of this novel nanocomposite revealed 89.2% (kobs = 1.7 × 10-2 min-1) and 76% (kobs = 8.3 × 10-3 min-1) degradation efficiencies of MB dye under UV and visible light irradiation at room temperature, respectively, and the surface area of the V2O5-Fe3O4/rGO nanocomposite was examined to be 705.8 cm2/g by N2 adsorption-desorption isotherms. In addition, electrochemical measurements determined the best OER performance of the ternary nanocomposite with the lowest overpotential (458 mV) and Tafel slope (132 mV dec-1) compared to the rGO substrate, Fe3O4, V2O5 nanoparticles, and binary nanocomposites. This work shows much enhancements in both photocatalytic and electrocatalytic activities due to the synergistic effect of the decorated GO support with V2O5 and Fe3O4 nanoparticles.

Composite material immobilized in 3D-printed support, an economical approach for electrochemical sensing of nimesulide

This work aimed to build a disposable electrode, cheap, and robust, with a maximum manufacturing value of US$ 0.02 per sensor, whose basic structure is a composite material (CM) immobilized on 3D support of acrylonitrile butadiene styrene (ABS), to the determination of Nimesulide (NIM) in different samples. The surface characterization of the electrodes was made by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The electrochemical response for NIM obtained was compared with a commercial Glassy Carbon electrode (GCE), where a 70 % increase in the analytical response was observed. The sensor was applied for the quantification of NIM by the square wave voltammetry (SWV) method in pharmaceutical formulations, tap water, synthetic urine, and breast milk. The optimized method presented a satisfactory linear range of 10 to 50 µmol/L, with a simple sample treatment, good precision (RSD < 3.38 %), and excellent detectability (limit of detection 0.018 µmol/L). Samples were spiked at three concentration levels to evaluate the accuracy of the method, obtaining recovery values from 96.2 to 112.8 %. Thus, the disposable proposed device proves to be a promising analytical tool for routine analysis of NIM in different samples with a minimum sample preparation step (simple dilution).

Development of a 3D disposable device for the electrochemical determination of diclofenac in different matrices.

In this work, the development of a disposable electrochemical device (US$ 0.02 per electrode) using a 3D printed support (3Ds) of acrylonitrile butadiene styrene (ABS) insulating filament with a composite material (CM) based on graphite and nail polish, immobilized on the support surface, was described for the electrochemical determination of diclofenac (DCF). The device was compared to the commercial glassy carbon electrode (GCE) and showed superior electroanalytical performance with approximately 1.8-fold higher current density. Additionally, an amperometric method for DCF determination in tap water, synthetic urine, and pharmaceutical formulation samples with the proposed electrode, using a flow injection analysis (FIA-AD) system, was developed. The optimized method presented excellent detectability (LOD = 0.47µmol L-1), with excellent precision and accuracy (relative standard deviation < 5.6%) and percent recovery from spiked samples ranging from 89 to 106%. In addition, the sensor showed optimal analytical frequency with approximately 108 injections per hour, which demonstrates the potential of this system using the proposed disposable electrode for implementation in routine analysis and quality control with good selectivity and sensitivity.

Enhanced OER properties from nanocomposites of Co3O4 and MOF derived N/S/Zn-doped porous carbon

In the present work, Co3O4 nanoparticles embedded in N/S/Zn- doped porous carbon matrices are synthesized and utilized as active materials to modify the commercial glassy carbon electrode (GCE) for enhanced and highly stable oxygen evolution reaction (OER). To design these nanocomposites, initially, a metal-organic framework (spherical ZnDTO) is synthesized by the complexation of Zn-salts and dithiooxamide (DTO) ligand, and N/S/Zn- doped porous carbon matrix (NSC) derived by carbonizing them at different temperatures. Then, to investigate the role of Zn on the catalytic performance of the materials, the thermally optimized carbon matrix is treated with a suitable acid. Further, hydrothermally synthesized Co3O4 nanoparticles are being used to form composites with these carbon matrixes. All the as-synthesized materials have been well-characterized by various tools for their structural and morphological associations. The best composite shows the onset overpotential of 480 mV vs. RHE close to ‘RuO2’ (460 mV vs. RHE) and has the lowest Tafel slope 62 mVdec−1. It excels in its current stability test for 7200 seconds at a static overpotential of 480 mV vs. RHE. It also exhibits continuous OER performance with a 130% increment in LSV current that reveals the catalyst's porous and non-corrosive nature. Finally, it has been proved with a thorough analysis that increased oxygen vacancies in the as-synthesized material are the protagonist to enhance the OER performance. At the same time, heteroatoms (N and S- atom) and Zn are also observed to enhance the electrocatalytic activity significantly.

Additively Manufactured Rotating Disk Electrodes and Experimental Setup.

This manuscript details the first report of a complete additively manufactured rotating disk electrode setup, highlighting how high-performing equipment can be designed and produced rapidly using additive manufacturing without compromising on performance. The additively manufactured rotating disk electrode system was printed using a predominantly acrylonitrile butadiene styrene (ABS) based filament and used widely available, low-cost electronics, and simplified machined parts to create. The additively manufactured rotating disk electrode system costs less than 2% of a comparable commercial solution (£84.47 ($102.26) total). The rotating disk electrode is also additively manufactured using a carbon black/polylactic acid (CB/PLA) equivalent, developing a completely additively manufactured rotating disk electrode system. The electrochemical characterization of the additively manufactured rotating disk electrode setup was performed using hexaamineruthenium(III) chloride and compared favorably with a commercial glassy carbon electrode. Finally, this work shows how the additively manufactured rotating disk electrode experimental system and additive manufactured electrodes can be utilized for the electroanalytical determination of levodopa, a drug used in the treatment of Parkinson’s disease, producing a limit of detection of 0.23 ± 0.03 μM. This work represents a step-change in how additive manufacturing can be used in research, allowing the production of high-end equipment for hugely reduced costs, without compromising on performance. Utilizing additive manufacturing in this way could greatly enhance the research possibilities for less well-funded research groups.

Development of modified graphite electrodes with nanoparticles and their application in the quantification of sucrose

AbstractBACKGROUNDDeveloping fast and reliable methods with little sample preparation has become increasingly important for process monitoring and control. Electrochemical methods stand out for their low cost and instrumental simplicity. Furthermore, electrodes with nanoparticles can improve the method's sensitivity and specificity. This study developed carbon paste electrodes modified with nanoparticles of copper and iron. In addition, cyclic voltammetry was performed using a low‐cost potentiostat designed for a Raspberry Pi single‐board computer. As a proof of concept, the constructed electrodes were tested with ferrocyanide and applied to quantify sucrose, and their performance was compared to that of the glassy carbon electrode.RESULTSThe nanoparticles were successfully synthesized, as confirmed by morphology and physicochemical characterization. Based on the adjusted R2, the electrode made with the addition of copper oxide nanoparticles has a similar performance to the commercial glassy carbon electrode. All electrodes' root mean square error (RMSE) values were approximately 10−4 mol L−1. The lowest values for the inverse of the analytical sensitivity for sucrose were obtained for the unmodified carbon paste electrode (9.54 × 10−6 mol L−1) and copper oxide nanoparticles electrode (5.30 × 10−6 mol L−1). These electrodes also had the lowest limits of detection (10−5 mol L−1) and, for the limit of quantification, all electrodes had similar values (10−2 mol L−1).CONCLUSIONIn general, superior performance of carbon paste electrodes was observed concerning the commercial glassy carbon electrodes. Compared to previous studies, the developed electrodes showed good sensitivity and the low cost of the electrochemical system stands out as the main advantage. © 2022 Society of Chemical Industry (SCI).

Disposable Paper-Based Biosensors: Optimizing the Electrochemical Properties of Laser-Induced Graphene

Laser-induced graphene (LIG) on paper substrates is a desirable material for single-use point-of-care sensing with its high-quality electrical properties, low fabrication cost, and ease of disposal. While a prior study has shown how the repeated lasing of substrates enables the synthesis of high-quality porous graphitic films, however, the process–property correlation of lasing process on the surface microstructure and electrochemical behavior, including charge-transfer kinetics, is missing. The current study presents a systematic in-depth study on LIG synthesis to elucidate the complex relationship between the surface microstructure and the resulting electroanalytical properties. The observed improvements were then applied to develop high-quality LIG-based electrochemical biosensors for uric acid detection. We show that the optimal paper LIG produced via a dual pass (defocused followed by focused lasing) produces high-quality graphene in terms of crystallinity, sp2 content, and electrochemical surface area. The highest quality LIG electrodes achieved a high rate constant k0 of 1.5 × 10–2 cm s–1 and a significant reduction in charge-transfer resistance (818 Ω compared with 1320 Ω for a commercial glassy carbon electrode). By employing square wave anodic stripping voltammetry and chronoamperometry on a disposable two-electrode paper LIG-based device, the improved charge-transfer kinetics led to enhanced performance for sensing of uric acid with a sensitivity of 24.35 ± 1.55 μA μM–1 and a limit of detection of 41 nM. This study shows how high-quality, sensitive LIG electrodes can be integrated into electrochemical paper analytical devices.

A pencil graphite-based disposable device for electrochemical monitoring of sulfanilamide in honey and water samples.

The present paper reports a simple, fast, and inexpensive process of manufacturing a disposable pencil graphite electrode (PGE) from widely available materials, which showed a reproducibility of at least 7.5%. The electrode was compared to the commercial glassy carbon electrode (GCE) and showed superior electroanalytical performance for sulfanilamide (SFA) with approximately 3.9-fold higher current density. Additionally, a displacement of the oxidation peak from approximately 80 mV to more cathodic regions was observed. Therefore, a method based on square wave voltammetry (SWV) was developed for the determination of the antimicrobial SFA in honey and tap water samples using the proposed sensor. The optimized method presented good detectability (LOD = 2.37 μmol L-1), with excellent precision and accuracy (relative standard deviation < 4.2%) and percent recovery from spiked samples ranging from 92 to 97%. In addition, the sensor did not suffer significant interference from sample matrix components and other commonly evaluated antimicrobials, which demonstrates the potential of these electrodes for implementation in routine analysis and quality control.

Simple Method for Preparing Customizable Pyrolyzed Photoresin Carbon Electrodes Using 3D Printing

We report an accessible fabrication procedure to prepare customizable pyrolyzed photoresin electrodes (PPE) for electroanalytical applications. A stereolithography 3D printer was used to pattern carbon containing photoresin on a quartz substrate before being pyrolyzed to yield a carbon electrode with X and Y dimensions ranging from mm to a minimum feature size of approximately 200 µm as determined by optical microscopy. Stylus profilometery was used to determine PPEs have an approximate step height of 600 nm. Atomic force microscopy was employed to examine the surface roughness of PPEs, which were found to have a rms roughness of approximately 25 nm. Cyclic voltammetry with hexaammineruthenium chloride was performed to examine the electrochemical behavior of the PPEs, which was consistent with the Randles-Sevcik equation and commercial glassy carbon electrodes.

Electrochemical sensing of pioglitazone hydrochloride on N-doped r-GO modified commercial electrodes.

In this paper, we explain the electrochemical sensing of commercially available pioglitazone hydrochloride (PIOZ) tablets on a nitrogen (N) doped r-GO (Nr-GO) modified commercial glassy carbon electrode (GCE) and a commercial screen printed graphite electrode (SPGE). Nr-GO is synthesized by the chemical reduction of graphene oxide (GO) and simultaneous insertion of an N-dopant by hydrazine monohydrate. Pristine GO itself is prepared by chemical exfoliation of bulk graphite. Upon chemical reduction, the exfoliated GO sheets restack together leaving behind the doped N-atom as evidenced by XRD and Raman spectroscopy. The N-atom exists in the pyrrolinic and pyridinic form at the edge of graphitic domains which is confirmed by XPS. The as-synthesized Nr-GO is used for the preparation of electro-active electrodes with the help of the GCE and SPGE. These electrodes have the capability to oxidize PIOZ by a diffusion dominated process as evidenced by the impedance spectroscopic technique. The differential pulse voltammetric responses of different concentrations of PIOZ are assessed over the Nr-GO modified GCE and SPGE, which exhibit better limits of detection (LODs) of 67 nM and 29 nM, respectively, compared to those from earlier reports. These assays exhibit non-interfering capability in the presence of various body interferents at pH = 7.0.

Quantifying Electrocatalytic Reduction of CO2 on Twin Boundaries

Summary A protocol relying on the use of silver nanostructures with well-defined dimensions and morphologies (e.g., nanocubes and nanowires) has been developed to differentiate and quantitatively determine the atom-specific activities of different surface atoms toward catalyzing electrochemical CO2 reduction reaction (CO2RR). The atom-specific activity of the twin-boundary edges (TBEs) is comparable to (or slightly higher than) that of the single-crystal edges (SCEs) formed from the crossing of two {100} surfaces, and it is on the order of ∼16 attoampere/atom (aA/atom) toward electrochemical CO2RR. This value is more than two orders higher than the atom-specific activity of the {100} surface atoms, i.e., ∼0.1 aA/atom. The high catalytic activity of the TBEs, which represent a class of commonly existing surface defects in stable metal nanostructures with face-centered cubic lattices, is consistent with the DFT calculations, in which the bridge-type binding configuration of COOH∗ at the TBEs stabilizes this intermediate to promote overall CO2RR.

Simple Electrochemical Characterization of ortho‐Carborane and some of its exo‐Skeletal Derivatives

AbstractElectrochemical behaviour of 12 icosahedral carboranes – ortho‐, meta‐ and para‐carborane with different exo‐skeletal substituents was investigated. The study was done using phosphate buffers, in some cases with 20 % and 30 % dimethyl sulfoxide (DMSO) addition to increase the solubility of studied compounds. Commercial glassy carbon electrode or home‐made screen printed electrodes were used. Distinct electrochemical responses were observed only for the ortho‐carborane and its exo‐skeletal derivatives. The study of different exo‐skeletal substituents on the electrochemical behaviour of the carboranes is crucial for the intended use of these compounds as electrochemical labels of biomolecules.

Simple Method for Preparing Customizable Pyrolyzed Photoresin Carbon Electrodes Using 3D Printing

We report an accessible fabrication procedure to prepare customizable pyrolyzed photoresin electrodes (PPE) for electroanalytical applications. A stereolithography 3D printer was used to pattern carbon containing photoresin on a quartz substrate before being pyrolyzed to yield a carbon electrode with X and Y dimensions ranging from mm to a minimum feature size of approximately 200 µm as determined by optical microscopy. Stylus profilometery was used to determine PPEs have an approximate step height of 600 nm. Atomic force microscopy was employed to examine the surface roughness of PPEs, which were found to have a rms roughness of approximately 25 nm. Cyclic voltammetry with hexaammineruthenium chloride was performed to examine the electrochemical behavior of the PPEs, which was consistent with the Randles-Sevcik equation and commercial glassy carbon electrodes. Hydrodynamic voltammetry in a microfluidic device was also demonstrated.

Double-pulse chronoamperometry using short times for the kinetic study of simple quasi-reversible electrochemical reactions at low overpotentials

This work presents a simple and fast way to determinate the standard heterogeneous rate constant (k0) of simple quasi-reversible electrochemical reactions based on the short time double-pulse chronoamperometry at low overpotentials. The value of k0 was determined for the faradaic reaction involving redox couples of iron complexes on a commercial glassy carbon electrode. The errors involved in this type of analysis were evaluated by finite difference numerical simulations, and accurate determinations of k0 values have proved to be possible at short times in the case where the charge transfer is considerably hindered in comparison to the mass-transfer of the electroactive species. A very good correspondence was observed between the experimental findings and the theoretical analysis involving the finite difference numerical simulation.

Construction of a paper-based electrochemical biosensing platform for rapid and accurate detection of adenosine triphosphate (ATP)

In this paper, a simple but efficient electrochemical biosensing platform was developed for ATP assay based on the preparation of paper-based working electrodes. In contrast to the electrochemical response of commercial glassy carbon electrode (GCE), improved voltammetric signals were achieved at the paper-based electrode. In particular, the surface contamination arising from oxidation product, a prominent challenge for ATP detection, was effectively eliminated by the paper-based system, endowing reliable analysis with high reproducibility. Moreover, the practical application value of the system was verified by assay of ATP in human serums, cancer cells, and normal cells with satisfactory results. Compared with the detection performances of traditional strategies, the advantages involved in the system were exhibited to be rapid, accurate, convenient, and inexpensive, which confer the proposed sensing platform promising for applications in public health as well as the fundamental research of molecular biology.

Comparison of unusual carbon-based working electrodes for electrochemiluminescence sensors

In this work, unconventional carbon-based materials were investigated for use in electrochemiluminescence (ECL) working electrodes. Precursors such as bamboo, pistachio shells, kevlar® fibers and camphor were differently treated and used as working electrodes in ECL experiments. After a proper process they were assembled as electrodes and tested in an electrochemical cell. Comparison among them and with a commercial glassy carbon electrode (GCE) shows a very good response for all of them thus demonstrating their potential use as disposable low-cost electrodes for early detection electrochemical analysis.

Emulsion‐Templated Macroporous Carbons Synthesized By Hydrothermal Carbonization and their Application for the Enzymatic Oxidation of Glucose

Carbon-based monoliths have been designed using a simple synthetic pathway based on using high internal phase emulsion (HIPE) as a soft template to confine the polymerization and hydrothermal carbonization of saccharide derivatives (furfural) and phenolic compounds (phloroglucinol). Monosaccharides can be isolated from the cellulosic fraction of lignocellulosic biomass and phloroglucinol can be extracted from the bark of fruit trees; however, this approach constitutes an interesting sustainable synthetic route. The macroscopic characteristics can be easily modulated; a high macroporosity and total pore volume of up to 98 % and 18 cm(3)g(-1) have been obtained, respectively. After further thermal treatment under inert atmosphere, the as-synthesized macroporous carbonized HIPEs (carbo-HIPEs) have shaping capabilities relating to interesting mechanical properties as well as a high electrical conductivity of up to 300 Sm(-1) . These conductive foams exhibit a hierarchical structure associated with the presence of both meso- and micropores that exhibit specific Brunauer-Emmett-Teller (BET) surface areas and DFT total pore volumes up to 730 m(2)g(-1) and 0.313 cm(3)g(-1) , respectively. Because of their attractive structural characteristics and intrinsic properties, these macroporous monoliths have been incorporated as a proof of principle within electrochemical devices as modified thin carbon disc electrodes. A promising two-fold improvement in the catalytic current is observed for the electrooxidation of glucose after the immobilization of a glucose oxidase-based biocatalytic mixture onto the carbo-HIPE electrodes compared to that observed if using commercial glassy carbon electrodes.

An amperometric sensor based on ionic liquid and carbon nanotube modified composite electrode for the determination of nitrite in milk

A novel carbon composite electrode has been fabricated using ionic liquid n-octylpyridinum hexafluorophosphate (OPFP) and single-walled carbon nanotube (SWCNT). This electrode combined the advantages of ionic liquid and SWCNT as well as the characteristics of the “bulk” composite electrodes. Compared with the commercial glassy carbon electrode (GCE) and the ionic liquid–graphite (IL-G) composite electrode, the ionic liquid–SWCNT (IL-SWCNT) composite electrode exhibited remarkable increase in the electron transfer rate for electroactive compound and significant decrease in the overpotential for the oxidation of nitrite. Based on the enhanced electrocatalytic activity for the oxidation of nitrite, a wide linear range from 1.0μM to 12.0mM with a low detection limit of 0.1μM was obtained. Furthermore, the IL-SWCNT electrode was applied to determine nitrite levels in milk samples. Experimental results showed that the proposed electrode could be used as an effective and sensitive sensor for the determination of nitrite.

Glassy carbon and boron doped glassy carbon electrodes for voltammetric determination of linuron herbicide in the selected samples

Abstract In this study the application of home-made unmodified (GC) and bulk modified boron doped glassy carbon (GCB) electrodes for the voltammetric determination of the linuron was investigated. The electrodes were synthesized with a moderate temperature treatment (1000°C). Obtained results were compared with the electrochemical determination of the linuron using a commercial glassy carbon electrode (GC-Metrohm). The peak potential (E p ) of linuron oxidation in 0.1 mol dm−3 H2SO4 as electrolyte was similar for all applied electrodes: 1.31, 1.34 and 1.28 V for GCB, GC and GC-Metrohm electrodes, respectively. Potential of linuron oxidation and current density depend on the pH of supporting electrolyte. Applying GCB and GC-Metrohm electrodes the most intensive electrochemical response for linuron was obtained in strongly acidic solution (0.1 mol dm−3 H2SO4). Applying the boron doped glassy carbon electrode the broadest linear range (0.005–0.1 µmol cm−3) for the linuron determination was obtained. The results of voltammetric determination of the linuron in spiked water samples showed good correlation between added and found amounts of linuron and also are in good agreement with the results obtained by HPLC-UV method. This appears to be the first application of a boron doped glassy carbon electrode for voltammetric determination of the environmental important compounds.