Electrode Modification Research Articles

PolyCitrulline Modified Glassy Carbon Electrode as a Voltammetric Sensor for the Simultaneous Determination of Metabolic Syndrome Biomarkers-Uric Acid and Tyramine

Abstract This article describes the development of a simple and sensitive voltammetric sensor for the simultaneous determination of Uric acid (UA) and Tyramine (TYM), which act as metabolic syndrome (Mts) biomarkers. The electropolymer of the naturally occurring amino acid citrulline (Cit) has been employed as the electrode modifier in this sensor. Glassy carbon electrode modified with poly citrulline has been characterized with the aid of techniques such as scanning electron microscopy (SEM) and SEM-energy dispersive X-ray analysis, surface area calculations and electrochemical impedance spectroscopy. Studies were carried out to optimize parameters like the cycles of polymerisation, supporting electrolyte and its pH. The sensor which offers fast determination of the analytes using square wave voltammetry possesses a limit of detection 1.32×10-8 M and 4.20×10-8 M for UA and TYM, respectively. The applicability of the sensor in body fluids has been proved through spike recovery analysis in artificial blood serum and urine samples. Interference on the voltammetric signals created by some dominant coexisting species of the analytes was found to be tolerable.

One-Step Electrochemical Modification of Pencil Graphite Electrode with Poly(DPASA-co-VP)-RuO2NPs and its Application for the Trace Analysis of Sumatriptan

One-Step Electrochemical Modification of Pencil Graphite Electrode with Poly(DPASA-co-VP)-RuO2NPs and its Application for the Trace Analysis of Sumatriptan

Molecularly Modified Electrodes for Efficient Triboelectric Nanogenerators

The integration of organic molecules into monolayers on triboelectric layers and electrodes has significantly improved the performance of triboelectric nanogenerators (TENGs) in recent years. By modifying surfaces at the molecular level, one can enhance durability, power density, and cost‐efficiency, leading to flexible, lightweight, and more efficient devices. A simple chemistry of organic monolayer formation allows a precise control over orientation, coverage, consistency, and functionality. These monolayers boost surface charge density and output voltage while influencing surface polarization and dipole interactions. This review focuses on recent advances in chemical modification of electrodes for controlling surface charge density and altering surface dipoles, emphasizing the significance of organic monolayers. A new concept of Schottky‐based TENGs is also introduced that explores chemically modified sliding surfaces. Furthermore, the importance of flexoelectricity and its contribution to triboelectricity is discussed. By addressing current challenges and outlining future directions, this review underscores the crucial role of surface chemistry in advancing TENGs.

Electrochemical characterization of carbon black in different redox probes and their application in electrochemical sensing

Carbon black - materials rich in carbon nanostructures - have been successfully applied as modifiers of electrochemical transducers, rivalling other carbon nanomaterials for cost and ease-of-use. Despite the remarkable promise of this nanomaterial, no study has yet comparatively characterised a wide range of different grades of carbon black for their utility in electrochemical sensors. Here, we explore several commonly-studied carbon black grades (N220, N234, N326, N330, N339, N375, N550, N660 and Lamp Black-101), alongside relatively newer grades (Printex®-200, Printex® G, Printex® XE-2B, and Printex® Zeta) for their application in electrochemical sensors. The effects of coating glassy carbon electrodes with carbon black on electrode performance were studied by cyclic voltammetry using three redox probes: ferri-/ferrocyanide (anionic probe molecules), ferrocenemethanol (neutral) and hexaammineruthenium (cationic). Raman Spectroscopy characterisation of the different grades associated a lower degree of graphitisation with superior electrode modifiers. Generally, modification increased the anodic peak current for ferri-/ferrocyanide probes; and lowered anodic potential for ferri-/ferrocyanide and hexaammineruthenium probes. Increases in peak current and potential observed at ferrocenemethanol are consistent with the increased tendency for this probe to adsorb to the surface of modified electrodes. N330 and Printex® XE-2B displayed the best electrocatalytic properties in terms of enhanced peak currents and lowered anodic overpotentials for the redox probes. CB grades were used to modify screen-printed carbon electrodes and the obtained sensors examined for anodic detection of reduced nicotinamide adenine dinucleotide (NADH) cofactor by cyclic voltammetry. Printex® XE-2B significantly improved the detection of NADH and was further used for chronoamperometric detection of NADH at low overpotentials. Grades N220, N375, N550 and P-G showed their suitability as enzyme scaffolds for sensor fabrication, as determined by their preservation of the activity of a NAD-dependent aldehyde dehydrogenase.

Developing dual detection platforms for the electrochemical quantification of homocysteine in biological samples

This study presents a novel dual electrochemical sensor developed using simple electropolymerization technique to detect and measure homocysteine (HC). The developed electrode modification was confirmed using FTIR, XRD, and SEM-EDX examinations. The poly(N-phenylanthranilic acid) modification of the glassy carbon electrode (GCE) and Screen-printed electrode (SPE) significantly enhanced the response for HC, surpassing the findings of previous studies. The improvement can be credited to the exceptional catalytic efficiency of the electro-polymer in electro-oxidizing HC. The electrochemical investigations were conducted utilizing analytical methods such as cyclic voltammetry and differential pulse voltammetry, with a 0.1 M phosphate buffer solution employed as the supporting medium. The poly-NPAA/GCE and poly-NPAA/SPE sensor has demonstrated exceptional sensing properties such as excellent selectivity, sensitivity, reproducibility and and repeatability. It is highly effective in identifying and quantifying HC. The exhibited linear range of both poly-NPAA/GCE and poly-NPAA/SPE are the widest, ranging from 1.0 to 2300.0 μM for poly-NPAA/GCE and from 3.0 to 3000.0 μM for poly-NPAA/SPE, making it the most remarkable result ever reported. The detection limit (LOD) of poly-NPAA/GCE was determined to be 0.165 µM while that of poly-NPAA/SPE was obtained as 0.618 µM. Furthermore, real-sample analysis was performed using biological fluids at the advanced sensor. Therefore, the fabricated poly-NPAA/GCE and poly-NPAA/SPE exhibited exceptional electrocatalytic capabilities for HC sensing, rendering it appropriate for continuous monitoring.

Chemometrics and electrochemistry joined hands to develop a novel and intelligent electronic device for simultaneous determination of malathion and diazinon in fruit juices: A progress in multidisciplinary studies

In this work, chemometrics and electrochemistry connected to each other to open a new way for assisting food industry specialists based on developing a novel electrochemical sensor for simultaneous determination of malathion (MT) and diazinon (DZ) in the presence of patulin (PT) and citrinin (CT) as uncalibrated interference in fruit juices. The sensor was fabricated based on modification of a glassy carbon electrode (GCE) by chitosan-ionic liquid (Ch-IL), electrodeposition of gold nanoparticles (Au NPs), drop-casting of multiwalled carbon nanotubes-IL (MWCNTs-IL), and electrochemical synthesis of dual templates molecularly imprinted polymers (DTMIPs) in which MT and DZ were used as templates. Effects of experimental variables on structure and response of the sensor were screened and optimized by Min Run screening and central composite design, respectively. After optimization, the third-order hydrodynamic differential pulse voltammetric (HDPV) data were generated based on changing modulation times and modulation amplitudes as instrumental parameters and modeled by N-PLS/RTL, U-PLS/RTL, U-PCA/RTL, APARAFAC, PARAFAC2 and MCR-ALS to select the best one to assist the sensor for ultra selective simultaneous determination of MT in the presence of PT and CT as uncalibrated interference in fruit samples. The results confirmed the MCR-ALS was the best assistance for DTMIPs/MWCNTs-IL/Au NPs/Ch-IL/GCE for simultaneous determination of MT and DZ in the presence of PT and CT as uncalibrated interference in both synthesis and real samples. Performance of the sensor assisted by MCR-ALS for ultra selective simultaneous determination of MT (0.1 pM to 12.5 pM, LOD=0.01 pM) and DZ (0.25 pM to 8.5 pM, LOD=0.15 pM) was really admirable which was comparable with HPLC with UV detection while it was faster, simpler and low-cost in comparison to HPLC-UV which motivated us to introduce it as a reliable method to assist food industry specialists for quality assurance purposes.

Electrochemical Oxidation of Glutathione in the Presence of Tryptophan at Carbon Paste Electrode Modified with Ni-Zn-Metal-Organic Frameworks/Graphene Oxide and Ferrocene Derivative

Glutathione (GSH) plays a vital physiological role as it is implicated in the progression and pathogenesis of a wide range of medical conditions, including diabetes, various types of cancer, and Parkinson’s disease. Due to the fundamental physiological importance of GSHand its relevance to numerous medical conditions, there is a clear need to develop simple, rapid, and cost-effective analytical methods. These methods could significantly aid in clinical diagnostics and guide the optimization of treatment approaches. This work reports the synthesis and characterization of a Ni-Zn-metal-organic framework/graphene oxide (Ni-Zn-MOF/GO) composite material, and its application as a modifier for a carbon paste electrode (CPE) in the electrochemical detection of GSH. The Ni-Zn-MOF/GO/ferrocene (FC)-modified CPE (Ni-Zn-MOF/GO/FC/CPE) was developed for this purpose. The Ni-Zn-MOF/GO/FC/CPE electrochemical sensor exhibited two linear response ranges for GSH: from 0.01–90.0 μM, and from 90.0–800.0 μM, with a detection limit estimated to be 0.003 μM. Importantly, Ni-Zn-MOF/GO/FC/CPE was shown to be suitable for the determination of GSH in the presence of tryptophan in real samples, such as human blood, GSH tablet and urine samples. The results highlight the potential of the Ni-Zn-MOF/GO/FC/CPE electrochemical sensor as a reliable and sensitive platform for the detection of GSH.

Electrochemical sensors for sensitive and selective detection of nitrite based on flexible gold microneedle like nanodendrites modified electrode

In this study, we present a new approach utilizing Au nanodendrites (Au NDs) to modify flexible screen-printed carbon electrodes (FSPCEs), offering an efficient platform for voltammetric sensing of nitrite ions in food samples. The FSPCEs are created with gold leaf-like nanodendrites through a simple, one-step electrochemical deposition process. The direct growth of these Au NDs occurs efficiently on the carbon-paste electrode, eliminating the need for binders or additional reducing agents and organic solvents, owing to the aforementioned matrix. The modified electrodes serve as promising sensing platforms for nitrite detection. The outcomes demonstrated that a significant amount of AuNPs with dendritic morphologies were dispersed throughout the FSPCE.These novel flexible electrodes act as effective electrocatalyst for NO2− oxidation due to their large electrochemical active surface area (ECSA), well-dispersed Au nanostructures, and high electrical conductivity. The optimized sensor exhibits a wide linear response range from 0.02 to 5.8 µM, with 1.0 nM limit of detection, an impressive sensitivity of 52.529 µA µM−1 cm−2 and a quick current response time (< 3 s) towards nitrite ions. Additionally, the suggested sensor demonstrates high selectivity, reproducibility, and stability. Furthermore, the FSPCEs are evaluated for their ability to selectively detect nitrite ions in various food samples such as tap water, drinking water, milk, and fruit juices, comparing the results with standard methods in real sample analysis. The fabricated sensors show promising potential for practical applications in food and environmental analysis. Consequently, Au NDs@FSPCE electrode emerged to be a novel platform for NO2− electrochemical detection. Because of their great affinity for analytical substances in solutions, gold nanodendrites supported on flexible screen-printed carbon electrodes (FSPCEs) are very useful for electrode modifications. Their increased effective surface area, which greatly raises the electrode's sensitivity and specificity for a range of analytical applications, is responsible for their high affinity.

Ultrasensitive electrochemical detection of 4-nitrophenol through flower-like mixed transition metal oxide anchored on reduced graphene oxide composites

4-Nitrophenol or para-nitrophenol is an organic water pollutant that has a direct impact on environmental pollution and human health. Therefore, developing sensitive electrochemical sensors is vital for monitoring environmental water samples to detect hazardous 4-nitrophenol. Herein, template-free zinc vanadate (ZV) micro-flowers were synthesized and anchored on reduced Graphene oxide (RGO) to modify the electrode surface for sensing and quantification of 4-nitrophenol. The fabrication of the as-prepared electrode modifier was confirmed by physicochemical and morphological characterizations. The synthesized ZV/RGO/GCE displayed well-defined reductive peak current at the potential of −0.7 V due to the hydrogenation of 4-nitrophenol. The increase in active sites and the larger surface area acquired by ZV and RGO were responsible for efficient sensing toward 4-nitrophenol. Under the optimized experimental parameters, CV and DPV techniques were carried out to investigate the electrochemical performance of ZV/RGO/GCE for the detection of 4-nitrophenol. The resultant cathodic current response was related linearly (0.01 µM to 1955 µM) to the concentration with the LOD of 0.009 µM. The developed sensor exhibited a good recovery range in the real-sample analysis in multiple water systems. The proposed ZV/RGO/GCE functions well as an effective electrode material for the determination of the perilous pollutant 4-nitrophenol in water samples by an electrochemical approach.

Emerging insights into the application of metal-organic framework (MOF)-based materials for electrochemical heavy metal ion detection

Heavy metal ions are one of the main sources of water pollution, which has become a major global problem. Given the growing need for heavy metal ion detection, electrochemical sensor stands out for its high sensitivity and efficiency. Metal-organic frameworks (MOFs) have garnered much interest as electrode modifiers for electrochemical detection of heavy metal ions owing to their significant specific surface area, tailored pore size, and catalytic activity. This review summarizes the progress of MOF-based materials, including pristine MOFs and MOF composites, in the electrochemical detection of various heavy metal ions. The synthetic methods of pristine MOFs, the detection mechanisms of heavy metal ions and the modification strategies of MOFs are introduced. Besides, the diverse applications of MOF-based materials in detecting both single and multiple heavy metal ions are presented. Furthermore, we present the current challenges and prospects for MOF-based materials in electrochemical heavy metal ion detection.

Nanosized hyperbranched cobalt and metal-free phthalocyanine intercalated with Pd–C matrix using PVA-TEOS as binder for admirable supercapacitor properties

The expanding global economy resulted mainly from consuming fossil fuels, which are scarce and cause prodigious environmental harm. Mankind is shifting towards sustainable, efficient and clean energy sources known as green energy. The storage of green energy is an urge of time, to fulfil the energy requirements. Supercapacitors are gaining popularity in the field of energy storage due to their excellent safety, cost-effectiveness, and environmental friendliness. The forthright strategy of using a nitrogen-rich phthalocyanine macrocycle as a nanosized particle is to increase surface area resulting in a high specific capacitance. Herein, an innovative approach has been made by synthesising nanosized hyperbranched metal-free/Co-Phthalocyanine characterized by various analytical and spectroscopic techniques. The morphology of the composite was confirmed through physicochemical characterization like BET, SEM, XRD and electrochemical features were studied through cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). The electrode modification was carried out using the binder Poly (vinyl alcohol)-Tetraethyl orthosilicate (PVA-TEOS) crosslinked hybrid solution. The intercalated nanosized palladium on carbon matrix with HBCoPc and HBPc at different ratios enhanced the performance of capacitance. Amongst all the ratios, HBCoPc: Pd–C with 30:70 ratio has demonstrated superior specific capacitance of 824.25 F g−1 at 0.5 A g−1. Additionally, the fabricated electrode of HBCoPc: Pd–C and HBPc: Pd–C has exhibited good capacitance retention of 84.03 % and 81.01 % over 5000 cycles, respectively. This work delivers a promising approach towards the development of high-performance supercapacitors using metal phthalocyanine/metal-carbon composites as a new way to manufacture devices for conversion and energy storage.

Electrochemical Analysis of Key Anticancer Herbal Drugs: Progress and Innovations in Emodin, Rutin, Berberine, Shikonin, and Sophoridine

Background: Anticancer herbal drugs have gained significant attention in pharmaceutical research due to their complex chemical profiles and multifaceted therapeutic effects. Electrochemical analysis has emerged as a powerful tool for studying these compounds, offering unique insights into their behavior and properties. Methods: This review examines recent advances in the electrochemical analysis of five key anticancer herbal drugs: emodin, rutin, berberine, shikonin, and sophoridine. Various electrochemical techniques, including cyclic voltammetry, differential pulse voltammetry, and square wave voltammetry, are discussed in relation to their application in detecting and characterizing these compounds. Results: Significant progress has been made in developing highly sensitive and selective electrochemical sensors for these herbal drugs. Nanomaterial-modified electrodes have consistently improved detection limits and expanded linear ranges. Compound-specific innovations in electrode modifications and measurement techniques have been tailored to the unique electrochemical properties of each drug. Conclusion: Electrochemical analysis of anticancer herbal drugs has advanced substantially, offering powerful tools for studying and utilizing these compounds in cancer research and treatment. Future directions include the development of multi-analyte sensors, integration with microfluidic technologies, and application of artificial intelligence for data analysis. Challenges remain in improving the stability of modified electrodes and standardizing protocols for sample preparation and analysis.

Novel usage of perinone polymer as solid contact in ion-selective electrodes

The paper presents the use of a new perinone polymer (PPer) as an intermediate layer and the development of a new type of potassium ion-selective electrodes with solid contact. The PPer layer was applied to the surface of a glassy carbon electrode using potentiodynamic polymerization from an electrolyte solution containing perinone precursors (Per). Subsequently, the surface of the electrode after application of the polymer was examined using a microscope and an optical profilometer. To check the quality of the prepared ion-selective electrodes, a series of tests were carried out and the analytical and electrical parameters of the electrodes were determined. Electrode modifications using PPer improved the electrode parameters, especially the stability and reversibility of the potential, compared to the control electrode covered only with an ion-sensitive membrane. The best electrode was the electrode modified with PPer applied in 10 cycles, which, as a result of the modification, allowed better parameters to be obtained – slope 58.86 mV/decade, LOD 1.2 × 10−6 M, linearity range 5 × 10−6 – 1 × 10−1 M. A very low short-term potential drift value of 2.7 × 10−4 mV/s was obtained as well as an extremely satisfactory SD value of 1.1 mV from E0 measurements. The modification also improved electrical properties and gave a negative result of the water layer test.

Enhancing microbial fuel cell performance for distillery wastewater treatment and bioelectricity generation: harnessing niacin as a redox mediator.

The role of redox mediators in improving electron transport from electrochemically active bacteria to the anode is crucial for enhanced bioelectricity output from microbial fuel cells (MFCs), which makes the selection of an ideal mediator very important. This study aims at exploring a new redox mediator niacin (vit B3) for enhanced bioelectricity generation in MFC while treating distillery wastewater through facile modification of anode electrode by niacin doping (MFC-NME) and simple application of niacin to the anolyte (MFC-NAA). Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) of NME confirmed the effective adsorption of niacin onto the carbon felt surface. Notably, MFC-NME exhibited a significantly higher power density (PD) of 6.36 W/m3 compared to MFC-NAA (4.59 W/m3) and control MFC (3.49W/m3). The charge transfer resistance (RCT) in MFC-NME (1.73 Ω) and MFC-NAA (2.06 Ω) were lowered by more than half than that in control MFC (4.33 Ω), which underscores the efficacy of niacin as a redox mediator. SEM analysis revealed improved bacterial attachment over the bioanode in the MFC-NME as compared to that of MFC-NAA and control MFC. Removal of chemical oxygen demand (COD) was higher in MFC-NAA (85%) and MFC-NME (80%) than in control MFC (73%) suggesting that niacin in the anolyte supported greater organic matter removal due to enriched microbial activity. Niacin used in anode modification shows great potential for improved electron transfer and enhanced bioelectricity production and supports greater wastewater treatment performance. The modified bioanode NME exhibits excellent stability.

Plasma-assisted surface modification of MXene/carbon nanofiber electrodes for electrochemical energy storage

Inferior ion diffusion and relatively low electrochemically active sites of MXene-based electrodes make them becoming a major challenge to develop advanced electrode. Surface modification of electrodes using non-thermal plasma is a great way to suppress these challenges through providing more space for energy storage and facilitating the diffusion of electrolyte ions. Herein, the effect of nitrogen and oxygen plasma treatments on MXene/carbon nanofiber electrode is reported to enhance the electrochemical performance. In this work, Ti3C2Tx MXene/CNF composites were fabricated using a hybrid needleless electrospinning/plasma method for the electrochemical energy storage. Surface modification of the composites was performed by a DBD plasma reactor under N2 and O2 gases at low-pressure glow discharge as a two-step plasma treatment process. The results revealed that total pore volume and the surface area of the plasma-treated Ti3C2Tx/CNF composite increased considerably due to the N2 and O2 plasma treatments. It was found that the electrochemical active surface area of the N2/O2-plasma-treated Ti3C2Tx/CNF electrode enhanced by approximately two times compared to the non-treated one, leading to the specific capacitance of 162 F/g at 1 A g−1 in a 2 M KOH electrolyte. The increase in electrochemical activity arises from separate doping of N2 and O2 plasma, which not only improves the pore structure and wettability, but also modifies the electrical conductivity and capacitance of the electrode. The N2/O2-plasma-treated Ti3C2Tx/CNF electrode achieved excellent cycling stability with 124 % capacitance retention after 10,000 cycles, while the capacitance retention of the pure N2 and O2-plasma-treated Ti3C2Tx/CNF electrodes as well as the non-treated one were 111 %, 105 % and 98 %, respectively. Additionally, an asymmetric supercapacitor N2/O2-plasma-treated Ti3C2Tx/CNF//AC based on the N2/O2-plasma-treated Ti3C2Tx/CNF as a positive electrode and activated carbon (AC) as a negative electrode was successfully constructed, which demonstrated an energy density of 26.3 Wh kg−1 with a power density of 750 W kg−1 at the current density of 1 A g−1 with excellent capacitance retention (102 %) after 5000 cycles. This work provides a highly efficient method for the surface modification of MXene-based electrodes through non-thermal plasma treatment.

Electrochemical detection of quercetin at a Pt nanoaggregate-decorated Ti3C2-modified electrode

The surface chemical state of the electrode modification material, particularly crystal defects, significantly affects electrochemical detection properties. In this study, Ti3C2 decorated by Pt nanoaggregates (Pt NAs-Ti3C2) with enhanced crystal defect was developed for quercetin detection, where Pt nanoaggregates on Ti3C2 exhibit improved dispersibility and smaller particle size, generating a more favorable environment for interfacial catalytic reactions. A large specific surface area, the Pt NAs-Ti3C2 composite is beneficial for the adsorption and transfer of quercetin on the electrode surface. In comparison to Pt nanoaggregates with complete crystals, the Pt NA-Ti3C2-modified glassy carbon electrode (Pt NA-Ti3C2/GCE) demonstrates superior quercetin detection capabilities, achieving a detection sensitivity of 72.3 μA μM−1 and an outstanding detection linear region of 0.1–1500 nM. Besides, the electrode showcases excellent reproducibility with RSD of 2.41 %, repeatability with RSD of 1.08 %, and long-term stability with 92.3 % of the original signal retained, and resistance to interference, achieving accurately and selectively quercetin detection even in the presence of other ions and compounds. In addition, the Pt NA-Ti3C2/GCE allows for precise quercetin detection in real-life samples. Our findings establish a theoretical guideline and furnish the material foundation for the development of high-performance electrochemical sensors.

Micro-droplet printed ion-selective membrane sensors for in situ monitoring of marine heavy metal ions

Fast, accurate, and reliable techniques for marine toxic heavy metal ions (HMI) detection are critical for the ecological environment and human health. One of the fatal drawbacks of traditional ion selective electrochemical sensors is that the modification of electrode cannot be accurately quantified, resulting in poor repeatability of the detection electrode and large error between the multi-electrode detection results. In order to tackle this challenge, this study presents ultra-fine micro-droplet printed electrodes for the in-situ detection of Cd2+, a carcinogenic and toxic HMI commonly found in the ocean. The ion selective membrane casting liquid was dispersed into tiny droplets with a diameter of micron through microfluidic technology, and the microdroplets were precisely arranged on the electrode surface. As a result, the modification error of electrode was reduced to pL level (accurate to 10 pL), which greatly improved the repeatability between electrodes prepared in different batches. The results of experiments with pure electrolyte, interference ions and artificial seawater indicated that the micro-droplet printed sensors possessed excellent properties of accuracy, precision, repeatability, and anti-interference. This novel micro-droplet printed sensor has the potential to capture an accurate picture of nearshore HMI in heterogeneous environments under shock conditions.

Electrochemical Sensor based on N-Doped Graphite/Aluminum Silicate Nanocomposite Modified Carbon Paste for Simultaneous Detection of Paracetamol and Pamabrom

We have developed an eco-friendly sensor through innovative modification of a carbon paste electrode with nanomaterials. This modification is based on employing a mixture of aluminum silicate and nitrogen-doped graphite nanocomposite (Al2SiO5/NG/CPE), introducing the first electrochemical approach for the voltammetric determination of a combination of paracetamol (PCM) and pamabrom (PAM), which is recognized as an over-the-counter remedy for menstrual cramp relief. N-doped graphite was prepared from graphite and urea using a metal-free soft nitriding method. The morphological characterization of the Al2SiO5/NG nanocomposite was investigated using transmission electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The experimental conditions were optimized using square wave voltammetry and cyclic voltammetry techniques to explore the impact of scan rate, pH, and concentration. The results exhibited good linearity across a wide concentration range of 0.2 nM–100.0 μM for both drugs. The limits of detection for PCM and PAM were 25 and 24 pM, respectively, while the limits of quantification were 88.3 and 80.0 pM, showing the proposed sensor’s exceptional sensitivity. Furthermore, the proposed sensor was employed to determine the PCM/PAM mixture in bulk powder, pharmaceutical dosage forms, biological fluids, and in the presence of toxic paracetamol metabolites.

Efficacy of Capacitive Deionization Flow Cell Fabricated with Carbon Nanomaterial Modified Electrodes

The supply of freshwater is becoming a serious global challenge. Capacitive deionization (CDI) has been recognized as apromising and smart desalination technique to solve it. Carbonaceous materials, due to their non-toxic characteristics, areused for filtration, adsorption, and water deionization. In this study, a newly designed, homemade low CDI system wasfabricated, and carbon as electrode material was prepared from waste leather through a one-step activated pyrolysis process. Carbonaceous materials prepared at different temperatures were characterized by Fourier-transform infrared (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. The charge storage capacity of the carbon materials casted on a glassy carbon electrode was evaluated using cyclic voltammetric and galvanostatic chargingdischarging techniques. The fabricated CDI system could be successfully used for the study of the removal capacity of NaCl from an aqueous solution. The removal capacity of carbon prepared at 600 °C from leather is 11.58 mgg1, which is about three times higher than commercial activated carbon at flow rate and applied potential of 23 mL min–1 and 1.0 V, respectively. Dhaka Univ. J. Sci. 72(2): 52-60, 2024 (July)

Amperometric Determination of Dopamine and Ascorbic Acid with a Carbon Paste‐Yttrium Oxide Electrode

AbstractThis report presents a new application for yttrium oxide (YOX) in the modification of carbon paste electrodes with excellent electroactivity for the independent detection of dopamine (DA) and ascorbic acid (AA). The surface of the YOX‐modified electrode was characterized with SEM and EDS. The electroactive properties of DP and AA were studied with cyclic voltammetry (CV), square wave voltammetry (SWV) and amperometry (Am). The activity of DA and AA increased by more than 100 % when YOX/CPE was used, which allowed us to obtain detection limits of 0.04 and 0.06 μmol/L for DA and AA, respectively. The usefulness of YOX/CPE was tested with real human urine, fresh orange juice and vitamin C tablets, and the results were acceptable.