Stripping Voltammetry Research Articles

Bismuth-MXene nanocomposite: A low-cost portable solution for zinc (II) detection in water for safer environmental monitoring

The development of a portable and cost-effective sensor for detecting zinc ions (Zn (II)) in water addresses a crucial need for real-time monitoring of heavy metal environmental contamination. To this, here, a novel bismuth-MXene (Bi2S3-MXene) nanocomposite-based sensor is developed for the rapid and selective detection of Zn (II) ions with a simple procedure. The exceptionally selective nanocomposites were capable of detecting Zn (II) through the square-wave anodic stripping voltammetry (SWASV) technique in a linearity range of up to 3 µg/mL, achieving limit of detection (LOD) of 7 ng/mL and limit of quantification (LOQ) of 22 ng/mL with a correlation coefficient of R2 =0.9825. Subsequently, the content of Zn (II) in real tap water and sea water was successfully determined for sensitivity and practical applicability. The developed sensor demonstrated several advantages for detecting Zn (II) in water, including a rapid setup process, fast detection times, high sensitivity, more selectivity and portability. While this study focuses on Zn (II) detection, the developed platform suggests it could potentially be adapted for detecting other heavy metals in future research. This work broadens the potential applications of portable nanomaterial-based sensors for regular environmental monitoring.

Electrochemical and microscopic study of a rotating disk Gold-Film electrode for voltammetric determination of arsenic (III)

This article is dedicated to the fabrication and thorough examination of the properties of a gold-film electrode (AuFE) intended for arsenic (III) determination using square-wave anodic stripping voltammetry (SWASV). The gold-film electrode was prepared ex-situ by potentiostatic electrodeposition of a gold layer onto a rotating glassy carbon electrode (GCE). Various deposition parameters were investigated and optimized, including the concentration of HAuCl4 solution (0.25 – 4 mM), deposition potential (0 – −600 mV), deposition time (120 – 1200 s), and electrode rotation speed (600 – 1500 rpm). Gold films prepared under different conditions were characterized using cyclic voltammetry (CV), optical microscopy, and scanning electron microscopy (SEM). The influence of AuFE characteristics on the parameters of the As(III) stripping peak was studied. Using the optimized AuFE, sensitivity and detection limit for As(III) of 0.468 μA/μg·L−1 and 1 μg/L, respectively, were achieved. The effects of interfering ions (Fe(III), Mn(II), Pb(II), Cu(II), Sn(IV), Tl(I)) on the As(III) response were investigated. The analytical utility of the optimized AuFE was validated for the quantitative determination of arsenic in tap water and seafood. The proposed procedure provides optimal conditions for the electrochemical preparation of gold-film electrodes aimed at routine arsenic monitoring.

A home-made nanoporous gold microsensor for lead(II) detection in seawater with high sensitivity and anti-interference properties.

A nanoporous gold microelectrode (NPG-μE) was fabricated and used for Pb(II) detection in seawater samples via square wave anodic stripping voltammetry (SWASV). The Au microelectrode (Au-μE) was fabricated by embedding a gold microfiber into a Pasteur pipette, and its surface was further modified by an anodization-electrochemical reduction (A-ECR) method, yielding the NPG-μE. The fabricated electrodes were characterized by cyclic voltammetry (CV) and field emission scanning electron microscopy (FE-SEM) for electrochemical and structural morphological investigations. SWASV results show a Pb(II) stripping peak at around -0.05 V vs. Ag/AgCl, sat. KCl, which is unusual for common Pb(II) detection (typically occurring at around -0.40 V) in anodic stripping voltammetry (ASV) analysis. The Pb(II) detection at less negative stripping potential is more beneficial. Hence, it exhibited anti-interference properties with Cd(II), which is attributed to the preferential deposition and stripping of the target analyte on the low-indexed crystal planes of the NPG structure. The calibration plot obtained by SWASV was linear in the concentration range of 0.1-10 μM, and the detection limit was found to be 57 nM (correlation coefficient of 0.9974). The NPG microsensor presented a 15-fold enhanced current response compared to Au-μE, with excellent sensitivity (27.2 μA μM-1 cm-2). The application of the NPG microsensor was examined by detecting Pb(II) in seawater samples, and a satisfactory performance was obtained.

Simultaneous quantification of Hg(II) and Pb(II) by square wave anodic stripping voltammetry using Bi/graphite electrode

In the present work, we report the synthesis and evaluation of a graphite-supported bismuth film working electrode (BiFE) in the simultaneous quantification of Hg(II) and Pb(II) at ppb levels. The BiFE was synthesized in-situ by electrodeposition in 1 M HNO3 as the supporting electrolyte at −0.5 V potential. A design of experiments and a response surface model (RSM) were developed to optimize the parameter of bismuth concentration ([Bi]) and deposition time (tdep) in the synthesis of the BiFE. The electrodeposition conditions of [Bi] = 3 mM and tdep = 10s proved to be the optimal conditions for the highest sensitivity and selectivity of the synthesized working electrode. For the quantification of Hg(II) and Pb(II), the electrochemical technique of square wave anodic stripping voltammetry (SWASV) was used by applying a deposition potential of −1 V in 1 M acetic acid buffer solution. The optimization of the factors analyzed in the design of experiments allowed the simultaneous detection of Hg(II) and Pb(II) at limiting levels of 1 ppb and 10 ppb, respectively. The calibration curves of Hg(II) and Pb(II) present an R2 of 0.988 and 0.982, respectively.

Highly sensitive determination of trace arsenic(III) onto carbon paste electrode modified with graphitic carbon nitride decorated Fe-MOF

An effective electrochemical sensor was developed to detect and determine of the As(III) by modifying the carbon paste electrode (CPE) with graphitic carbon nitride decorated with iron-based metal-organic frameworks (Fe-MOF/g-C3N5). The differential pulse anodic stripping voltammetry (DPASV) method was used to analyze As(III) ions in a phosphate buffer solution (0.10 M, pH = 5). Fe-MOF/g-C3N5/CPE showed high sensitivity (4.24 μA μg−1 L), satisfactory linear range (0.50 μg L−1–5.00 μg L−1 and 5.00 μg L−1–30.00 μg L−1), and low detection limit (LOD, 0.013 μg L−1). The prepared sensor was showed an excellent repeatability and selectivity, and successfully used for determination of the As(III) ion in ambient waters and apple juice samples.

Advanced electrochemical detection of arsenic using platinum-modified boron-doped diamond by anodic stripping voltammetry

Background: Platinum-modified boron-doped diamond (BDD) electrodes were effectively fabricated through a combination of wet seeding and electrodeposition techniques. Methods: This research involved the utilization of various chemicals and apparatus, the modification of boron-doped diamond (BDD) electrodes with platinum using wet seeding and electrodeposition, and the detection of As3+ and As5+ using a phosphate buffer solution and anodic stripping voltammetry (ASV). Findings: Characterization using Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) confirmed the successful deposition of 1.54% platinum on the BDD surface. These modified electrodes were employed as sensors for arsenic species (As³⁺ and As⁵⁺) using anodic stripping voltammetry (ASV) in a 0.1 M phosphate buffer solution at pH 6. Under optimal conditions, including a deposition potential of -500 mV, a deposition time of 150 s, and a scan rate of 200 mV/s, the linear detection of As³⁺ and As⁵⁺ was achieved within a concentration range of 0 to 100 ppb (R² = 0.9797 and 0.9903, respectively). Prior to ASV detection of As⁵⁺, a pretreatment step involving the addition of 0.1 M NaBH₄ was necessary to reduce As⁵⁺ to As³⁺. The detection limits for As³⁺ and As⁵⁺ were determined to be 16.50 ppb and 8.19 ppb, respectively. Conclusion: This research highlights the potential of BDD/Pt electrodes in environmental monitoring and arsenic detection applications and demonstrates the method's efficacy for the speciation analysis of arsenic species. Novelty/Originality of this Study: This research pioneers the use of platinum-modified boron-doped diamond electrodes for the speciation analysis of arsenic, offering a promising new approach for environmental monitoring applications.

Highly sensitive turn-on electrochemical sensing of organophosphorus pesticides by integration of homogeneous reaction and heterogeneous catalytic signal amplification

Enzyme-inhibited electrochemical sensor is a promising strategy for detecting organophosphorus pesticides (OPs). However, the poor stability of enzymes and the high oxidation potential of thiocholine signal probe limit their potential applications. To address this issue, an indirect strategy was proposed for highly sensitive and reliable detection of chlorpyrifos by integrating homogeneous reaction and heterogeneous catalysis. In the homogeneous reaction, Hg2+ with low oxidation potential was employed as signal probe for chlorpyrifos detection since its electroactivity can be inhibited by thiocholine, which was the hydrolysate of acetylthiocholine catalyzed by acetylcholinesterase. Additionally, Co,N-doped hollow porous carbon nanocage@carbon nanotubes (Co,N-HPNC@CNT) derived from ZIF-8@ZIF-67 was utilized as high-performance electrode material to amplify the stripping voltammetry signal of Hg2+. Thanks to their synergistic effect, the sensor exhibited outstanding sensing performance, excellent stability and good anti-interference ability. This strategy paves the way for the development of high-performance OP sensors and their application in food safety.

Silica graphite as an ink additive for stencil printed electrodes: A novel approach for electroanalytical determination of sulfanilamide

Silica-graphite composites present a high surface area, mechanical and chemical stability, and high functionality to be applied in electrochemical sensing. Indeed, those materials have been successfully employed to build composite electrodes such as carbon paste electrodes for a wide range of applications. Despite excellent performance, this kind of electrodes have been replaced by stencil printed electrodes (SPEs), emerging as a scalable alternative for manufacture offering sensors disposables, low-cost, customizable, and miniaturized. Based on this, herein a novel silica-graphite (SiG) composite is described as an ink additive aiming scalable production of SPEs with high functionality and surface area. The SPE as well as SiG were characterized by electrochemical impedance spectroscopy, scanning electron microscopy, thermogravimetric analysis, and contact angle. After an accumulation step, SiG-SPE pretreated has shown a significant improvement on oxidation of sulfanilamide compared with unmodified SPE. Electrochemical surface activation and pre-concentration conditions were investigated to enhance sensitivity and selectivity. Under optimized conditions, silica-graphite stencil printed electrode (SiG-SPE) was employed for the electrochemical determination of sulfanilamide by using square wave-adsorptive stripping voltammetry (SWAdSV). It was possible to achieve a linear dynamic range (LDR) from 2 to 20 mmol L−1 with a limit of detection (LOD) and quantification (LOQ) of 0.34 and 1.13 mmol L−1, respectively. The stability of the sensors was evaluated over five weeks, and a decrease of around 5.5 % in response was observed compared to fresh electrodes. SiG-SPE also presented high selectivity and low matrix interference for sulfanilamide determination with a recovery range of 96.2–100.1 % for urine and 98.2–106.1 % for commercial fat milk. Those results suggest that SiG is a promising ink additive for the production of low-cost and high-performance sensors, showing enhanced analytical properties, mechanical resistance, and chemical stability.

Highly sensitive and highly selective lead ion electrochemical sensor based on zn/cu-btc-nh2 bimetallic MOFs with nano-reticulated reinforcing microstructure

Identifying ultra-trace amounts of divalent lead ions (Pb2+) with high response and selectivity, continues to be a pressing issue in identifying environmental pollutants and preventing health complications. This paper details how the in-situ electrodeposited Zn/Cu-BTC-NH2 metal-organic frameworks (MOFs) boosts Pb2+ concentration for amino adsorption and facilitates ion transfer between Cu element and Pb2+. The modified coating of the glassy carbon electrode (GCE) exhibits a unique nano-reticulated structure loaded with octahedron particles, the nano-reticulated structure ensures the structural strength of the modified electrode layer, while the loaded octahedral particles enhancing electrocatalytic activity. The ultra-trace detection of Pb2+ at concentrations below μg·L−1 is accomplished by using the square wave anodic stripping voltammetry (SWASV) method, the fabricated Zn/Cu-BTC-NH2 modified electrode signifies a detection threshold of 0.021 μg L−1 and a clearly ascending linear interval prior to the rise in Pb2+ concentration to 120 μg L−1. The reported electrochemical method for the precise identification of Pb2+ in water-based solutions offers a practical approach for modifying MOFs materials and detecting heavy metal ions.

Effect of Temperature on the Removal of Interferences in the Voltammetric Procedure for the Determination of Cr(VI).

The aim of this paper was to investigate the effect of temperature on the removal efficiency of surfactant-induced interferences. Surfactants were removed as a result of mixing with XAD-7 resin. The study was carried out using the example of Cr(VI) determination by adsorption stripping voltammetry (AdSV). Measurements were carried out using a solution containing Cr(VI), acetate buffer (pH = 6.2), DTPA, KNO3, and different surfactants. Ten mL of the solution was mixed with 0.5 g of XAD-7 resin at different temperatures for 5 min prior to voltammetric measurement. The effect of the mixing temperature of the sample with the resin on the voltammetric Cr(VI) signal in the presence of different surfactants was studied in the range from 20 to 60 °C. The proposed method of removing interference from surfactants by mixing the sample with the XAD-7 resin at 60 °C was used for the determination of trace amounts of Cr(VI) in river water containing non-ionic, anionic, cationic surfactants, and biosurfactants.

One‐pot hydrothermal biochar obtained from malt bagasse waste as an electrode‐modifying material towards the stripping voltammetric sensing of lead

AbstractPb2+ ions are highly toxic to living beings because they tend to bioaccumulate in the body. For this reason, the development of simpler, low‐cost, and easy‐to‐operate techniques that can detect and quantify low concentrations of metal ions would help to identify contaminating media and improve public health. This work proposes a Pb2+ voltammetric sensor based on a carbon paste electrode modified with hydrothermal biochar (hydrochar, HC) obtained from malt bagasse waste (HC/CPE). The obtained hydrochar was characterized by zero‐charge point, FT‐IR, XRD and thermogravimetry. The differential pulse adsorptive anodic stripping voltammetry (DPAdASV) technique was used to perform the Pb2+ determination. After optimizing important parameters for detecting Pb2+ ions and the parameters of the voltammetric technique employed, a linear response range of 0.50 to 7.06 μmol L−1 with a limit of detection (LOD) and limit of quantification (LOQ) of 55.0 and 181.5 nmol L−1 were achieved, respectively. The developed voltammetric procedure was applied towards the Pb2+ determination at tap water and river water samples, with excellent recoveries (ranging of 91.19 to 109.22 %), proving that the HC‐based electrode has great potential for detecting Pb2+ ions. Hydrothermal carbonization allowed the biomass to be converted into functionalized hydrochar, eliminating the need for subsequent functionalization/activation steps for use as a Pb2+ adsorbing material on the electrodic surface. The proposed sensor also proved to be easy to assemble and environmentally friendly by using biomass waste as the carbon material. Thus, the proposed sensor adds to the literature the possibility of simple and easy detection of metal ions with a waste reuse bias.

Bismuth Film along with dsDNA-Modified Electrode Surfaces as Promising (bio)Sensors in the Analysis of Heavy Metals in Soils.

Heavy metals constitute pollutants that are particularly common in air, water, and soil. They are present in both urban and rural environments, on land, and in marine ecosystems, where they cause serious environmental problems since they do not degrade easily, remain almost unchanged for long periods, and bioaccumulate. The detection and especially the quantification of metals require a systematic process. Regular monitoring is necessary because of seasonal variations in metal levels. Consequently, there is a significant need for rapid and low-cost metal determination methods. In this study, we compare and analytically validate absorption spectrometry with a sensitive voltammetric method, which uses a bismuth film-plated electrode surface and applies stripping voltammetry. Atomic absorption spectroscopy (AAS) represents a well-established analytical technique, while the applicability of anodic stripping voltammetry (ASV) in complicated sample matrices such as soil samples is currently unknown. This sample-handling challenge is investigated in the present study. The results show that the AAS and ASV methods were satisfactorily correlated and showed that the metal concentration in soils was lower than the limit values but with an increasing trend. Therefore, continuous monitoring of metal levels in the urban complex of a city is necessary and a matter of great importance. The limits of detection of cadmium (Cd) were lower when using the stripping voltammetry (SWASV) graphite furnace technique compared with those obtained with AAS when using the graphite furnace. However, when using flame atomic absorption spectroscopy (flame-AAS), the measurements tended to overestimate the concentration of Cd compared with the values found using SWASV. This highlights the differences in sensitivity and accuracy between these analytical methods for detecting Cd. The SWASV method has the advantage of being cheaper and faster, enabling the simultaneous determination of heavy elements across the range of concentrations that these elements can occur in Mediterranean soils. Additionally, a dsDNA biosensor is suggested for the discrimination of Cu(I) along with Cu(II) based on the oxidation peak of guanine, and adenine residues can be applied in the redox speciation analysis of copper in soil, which represents an issue of great importance.

Rapid sequential determination of the explosives 2,4,6-trinitrotoluene and cyclotrimethylenetrinitramine in forensic samples employing a graphite sheet sensor and cyclic square-wave stripping voltammetry.

The development of a portable analytical procedure is described for rapid sequential detection and quantification of the explosives 2,4,6-trinitrotoluene (TNT) and cyclotrimethylenetrinitramine (RDX) in forensic samples using a graphite sheet (GS). A single GS platform works as a collector of explosive residues and detector after its assembly into a 3D-printed cell. The detection strategy is based on cyclic square-wave stripping voltammetry. The cathodic scan from + 0.1 to -1.0V with accumulation at 0.0V enables the TNT detection (three reduction peaks), and the anodic scan from + 0.2 to + 1.55V with accumulation at -0.9V provides the RDX detection (two oxidation processes). Low detection limit values (0.1 µmol L-1 for TNT and 2.4 µmol L-1 for RDX) and wide linear ranges (from 1 to 150 µmol L-1 for TNT and from 20 to 300 µmol L-1 for RDX) were obtained. The sensor did not respond to pentaerythritol tetranitrate (PETN), which was evaluated as a potential interferent, because plastic explosives contain mixtures of TNT, RDX, and PETN. The GS electrode was also evaluated as a collector of TNT and RDX residues spread on different surfaces to simulate forensic scenarios. After swiping over different surfaces (metal, granite, wood, cloths, hands, money bills, and cellphone), the GS electrode was assembled in the 3D-printed cell ready to measure both explosives by the proposed method. In all cases, the presence of TNT and RDX was confirmed, attesting the reliability of the proposed device to act as collector and sensor.

Simultaneous quantification of cadmium and lead ions using β-cyclodextrin functionalized poly(amino acid) electrochemical sensor

Heavy metals (HMs) are well-known environmental pollutants that threaten the life forms. The content of HMs in water must be constantly monitored as people are concerned about the ecosystem health, food safety and human health. In this work, a novel green composite consisting of amino acid (AA) and β-cyclodextrin (β-CD) was employed in constructing an electrochemical sensor. The fabricated sensor can be utilized for simultaneous detection of heavy metal ions (HMIs), including cadmium(II) ion (Cd2+) and lead(II) ion (Pb2+), by utilizing the distinctive potential difference between them as the detection signals. Such electrochemical sensor has several merits over the conventional detection approaches due to its portability, flexibility and simplicity. A green approach was used in the preparation of electrode in which β-CD and l-cysteine (Cys) were separately electropolymerized onto the electrode surface without linker in aqueous solution. Electrode fabrication was carried out by layer-by-layer electropolymerization, forming a thin polymeric film with abundant functional groups responsible for anchoring metal ions. Chemical and physical characterizations of modified electrodes were performed to validate the successful synthesis of polymeric film. Under optimal conditions, the developed electrode demonstrated promising simultaneous detection of Cd2+ and Pb2+ in real water samples through square wave anodic stripping voltammetry (SWASV) analysis, with results comparable to conventional methods employing inductively coupled plasma mass spectrometry (ICP-MS). The fabricated sensor revealed sensitivities of 346.26 μAμM-1cm−2 and 250.54 μAμM-1cm−2, and limit of detections (LODs) of 1.13 nM for Cd2+ and 0.53 nM for Pb2+, over the linear ranges of 3.42–700 nM and 1.60–700 nM, respectively. The developed sensor demonstrated a high selectivity, sensitivity, and stability, along with high reproducibility and low LOD over a wide linear range.

Anodic stripping voltammetry of arsenic determination with edible mushroom-nafion-modified glassy carbon electrode

An edible Mushroom-Nafion modified glassy carbon electrode (M2N5-GCE) was prepared using a homogeneous mixture varying the concentrations of these, in addition to the origin of the mushroom (Shiitake, Lentinula edodes, M1 and Abrantes, Agariscus bisporus, M2) and applied to the As(III) determination by anodic stripping voltammetry. After choosing the optimal conditions in the preparation of the electrode, the second stage was to study the effects of various parameters such as supporting electrolyte, pH, accumulation potential, and time (Eacc, tacc). The optimum experimental conditions chosen were Britton Robinson buffer 0.01 mol L−1 pH:4.6; Eacc: −1.0 and tacc: 60 s obtaining a signal of oxidation of As(0) to As(III) about 0.08 V. Peak current was proportional to arsenic concentration over the 19.6–117.6 μg L−1 range, with a 3σ detection limit of 13.4 μg L−1. The method was validated using As(III) spiked tap water from the laboratory with satisfactory results (RE:3.0 %). Finally, the method was applied to the determination of As(III) in water samples from the Loa River (Northern Chile) in the presence of As(V) in a concentration >20 times higher (RE: 2.3 %).

New perspective on the electrodeposition of Pb, Cd and Zn in electrode modified with bismuth film: A theoretical–experimental approach

Understanding electrode-analyte interactions at the atomic level is vital for improving analytical techniques, yet the complexity of these interactions poses a significant challenge for refinement.In this study, we investigate the detection of transition metals using Bi film electrodes, combining Density Functional Theory (DFT) simulations with experimental Anodic Stripping Voltammetry (ASV). Our experiments focus on the electrodeposition and detection of Zn2+, Cd2+, and Pb2+using Bi-modified carbon electrodes. The ASV experiments reveal a notably higher sensitivity for Pb2+detection compared to Zn2+and Cd2+, whether evaluated individually or simultaneously. DFT calculations demonstrate that the higher adsorption energy of Pb on the Bi surface promotes a uniform distribution of Pb atoms, resulting in a homogeneous phase. Conversely, Cd and Zn tend to present lower adsorption energies and form metallic clusters, leading to phase segregation. The correlation between theoretical and experimental data suggests that a more uniform deposition of Pb on the electrode surface facilitates a regular sweep in the redissolution step, achieving a detection limit as low as 0.062 nM for Pb. This synergistic approach not only enhances our understanding of electrode-analyte interactions but also provides valuable insights for optimizing electrode materials and detection methodologies in analytical chemistry.

Copper Adsorption by a Clay from Central Ivory Coast: Analysis by Differential Pulse Anodic Stripping Voltammetry

Heavy metals such as copper are not only a problem for air pollution: they are bio persistent, disrupt ecosystems, damage soils, surface waters, forests, and crops, and accumulate in the food chain. The aim was to propose effective methods for quantifying and decontaminating wastewater containing copper. In this study, the treatment of copper(II)-containing wastewater was carried out using clay, and the concentration of Cu2+ was monitored using the differential pulse anodic stripping voltammetry method. Physical characterization revealed the porous nature of our clay. Furthermore, the kinetic study of Cu2+ adsorption on clay is adapted to the pseudo-order 2 kinetic model, and the appropriate isotherm is that of Langmuir with an equilibrium time of 20 min. Cu2+ adsorption is maximal at pH = 6. The maximum monolayer adsorption capacity was found to be 66.54 mg/g.

Development and Characterization of a Sol-Gel-Functionalized Glass Carbon Electrode Probe for Sensing Ultra-Trace Amounts of NH3 and NH4+ in Water.

This study centers on the development and characterization of an innovative electrochemical sensing probe composed of a sensing mesoporous functional sol-gel coating integrated onto a glassy carbon electrode (sol-gel/GCE) for the detection of NH3 and/or NH4+ in water. The main interest for integrating a functional sol-gel coating onto a GCE is to increase the selective and sensing properties of the GCE probe towards NH3 and/or NH4+ ions. The structure and surface morphology of the newly developed sol-gel/GCE probe were characterized employing scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic light scattering (DLS), and Fourier-transform infrared (FTIR), while the electrochemical sensing properties were evaluated by Berthelot's reaction, cyclic voltammetry (CV), and adsorptive square wave-anodic striping voltammetry (Ads SW-ASV). It is shown that the newly developed sol-gel coating is homogeneously deposited on the GCE with a sub-micron and uniform thickness close to 630 nm and a surface roughness of 25 nm. The sensing testing of the sol-gel/GCE probe showed limits of detection and limits of quantitation of 1.7 and 5.56 nM of NH4+, respectively, as well as a probe sensitivity of 5.74 × 10-1 μA/μM cm-2. The developed probe was fruitfully validated for the selective detection of NH3/NH4+ in fresh and sea water samples. Computed Student texp (0.45-1.25) and Fexp (1.69-1.78) (n = 5) tests were less than the theoretical ttab (2.78) and Ftab (6.39) at 95% probability.

Effect of electrophoretic deposition for selective detection of Pb2+ ions using nitrogen and sulphur-doped reduced graphene oxide

Lead is very hazardous, as it is present in environmental samples, and it causes severe health problems affecting neurological, cardiac, genital, and mental illnesses owing to exposure to even a trace amount. The achievement of selective detection of Pb2+ ions is challenging due to interfering relevant metal ions. Hence, in this work, we have synthesized the Nitrogen and Sulphur N and S-doped reduced graphene oxide (NS-rGO) and fabricated it using electrophoretic deposition (EPD) in glassy carbon electrode (GCE) and Bi film deposition (Bi/EPD-NS-rGO/GCE) for selective detection of Pb2+ ions. The synthesized materials were characterized to confirm their functionalities, elemental analysis, and morphology. Further, the electrochemical behaviours were also carried out through Cyclic Voltammetry (CV) and Electrochemical Impedimetric spectroscopy (EIS) studies. The above-modified electrodes were utilized for selective detection of Pb2+ in the presence of Cd2+ ionsusing the differential pulse anodic stripping voltammetry (DPASV) method. The electrode modified with NS-rGO using the EPD method, along with a thin film of Bi that was electrodeposited, has better and more selective catalytic activity for sensing Pb2+ ions. The linear working response was found to be in the range of 100–2200 nM with a limit of detection (LOD) of 0.180 nM and verified as 144 times lower than the recommended level (26 nM) by World Health Organization (WHO) and United States Environmental Protection Agency (USEPA). The developed sensor was further applied to the selective detection of Pb2+ ions in tap water and river water, and it shows good recovery. The Bi/EPD-NS-rGO/GCE will explore a new pathway for the simple and selective detection of Pb2+ ions.

Selective Recognition of Lead and Cadmium in Potable Water Using Single Polypyrrole Nanowire Decorated with Cobalt Oxide Nanoparticles Electrode

The fabrication and characterization of a high-performance, robust, and highly sensitive sensor based on a single polypyrrole nanowire (sPpy NW) decorated with cobalt oxide nanoparticles (CoOxNPs) for the selective recognition of lead (Pb2+) and cadmium (Cd2+) in potable water are described in this paper. The electrodeposition technique was used to prepare the sPpyNW/CoOxNPs assembly, and square wave anodic stripping voltammetry (SW-ASV) was used to assess sensor performance. Optimizing sensor performance, such as deposition time, deposition potential, and supporting electrolyte, was used to assess for best sensor performance. The developed sensor exhibited excellent linearity and the linear range for the detection of individual Cd2+ and Pb2+ ions was determined to be 0.00 to 0.11 μM and 0.00 to 0.12 μM, respectively. The detection limits observed for both Pb2+ and Cd2+ sensors are 0.22 μM (R2 = 0.9520) and 0.013 μM (R2 = 0.9723), respectively. The linear range for the detection of Pb2+ and Cd2+ sensors present in the same sample was determined to be 0.00 to 0.09 μM, with a detection limit of 0.026 μM (R2 = 0.8726) and 0.013 μM (R2 = 0.9468) for Pb2+ and Cd2+, respectively. The observed results revealed that the functionalization of CoOxNPs on the surface of a sPpyNW electrode seems to be a very effective way of developing a sensitive, selective, and stable electrochemical sensor for Pb2+ and Cd2+ions.