Stripping Voltammetry Method Research Articles

Material Design of a Chromium Imprinted Polymer and its Application as a Highly Selective Electrochemical Sensor for Determining Chromium Ion at Trace Levels

AbstractThis study investigates the development of a Cr (VI)‐selective electrode based on Cr (VI) imprinted polymer nanoparticles and its application in detection of chromium ions by differential pulse voltammetry. In methanol, precipitation polymerization of meta‐acrylate acid (the functional monomer), 2, 2′‐azobisisobutyronitrile (the initiator), ethylene glycol dimethacrylate (the cross‐linker), 1, 5‐Diphenylcarbazide (the chromium‐binding ligand), and chromium ions (the template ion) produced IP‐NPs. After polymerization, Cr (VI) was leached out from the polymer nanoparticles using NaOH/EDTA 0.5/0.1 mol L−1 to create holes for Cr(VI). After sorption of Cr (VI) ions and reduction to metallic shape, the detection method of differential pulse stripping voltammetry was performed on a carbon paste electrode modified with IP‐NPs. The response of electrodes modified with IP‐NPs differed significantly from that of electrodes modified with non‐IP‐NPs. The modified electrode reacts to Cr (VI) linearly in the 0.1 nM to 10.0 nM range with sensitivity of 0.9594 nA/nM and linearly in the 10.0 nM to 100.0 nM range with sensitivity of 0.1958 μA/μM. At signal to noise of 3, the sensor‘s method detection limit was 30 pM. The sensor was employed to detect Cr (VI) traces in ambient water samples that had been contaminated.

Vibrating boron-doped diamond electrode: A new, durable and highly sensitive tool for the detection of cadmium

In this paper, a vibrating boron-doped diamond (BDD) electrode electroanalytical device and respective method for the analysis of ultralow concentrations of Cd(II) in water were studied. The enhanced mass transfer on the electrode surface was studied using Ru(NH3)6Cl3. Vibration with 133 Hz frequency enhanced the Ru(III) to Ru(II) reduction by 92.6% compared to a static electrode. The peak current of the anodic stripping voltammetry (ASV) method employed was increased by a factor of 5.3 and 4.7 for 10 and 30 μg L−1 Cd(II) concentrations, respectively, when a frequency of 200 Hz was used. A calibration plot with two linear regions was resolved between 0.01 and 1 μg L−1 and 1–30 μg L−1 with the LOD and LOQ of 0.04 μg L−1 and 0.12 μg L−1, respectively. The applicability of the device and the respective method in the analysis of real environmental samples was successfully verified by analysis of river samples and comparing the results with the ICP analysis presenting high reproducibility and trueness. According to the results of this research, the vibrating BDD electrode with the ASV method has excellent analytical performance without surface modification or regular replacement or polishing of the electrode surface. Combining the exceptional electrochemical and chemical properties of BDD with enhanced mass transfer and signal strength of vibrating electrodes makes the system especially suitable for on-site and online analysis of heavy metals.

Dual-Shaped Silver Nanoparticle Labels for Electrochemical Detection of Bioassays.

In this paper we demonstrate the use of dual-shaped silver nanoparticles (AgNPs) as detection labels for electrochemical bioassays. The key finding is that by using AgNP labels having two different shapes simultaneously, the limit of detection (LOD) for the assays is lowered compared to using either of the two shapes separately. The two shapes were silver nanocubes (AgNCs) having edge lengths of 40 ± 4 nm and spherical AgNPs (sAgNPs) having diameters of 20 ± 3 nm. Two different bioassays were examined. In both cases the Ag labels were functionalized with antibodies. In the one assay, the labels are directly linked to a second antibody immobilized on magnetic beads. In the second assay, the antibodies on the AgNP labels and the antibodies on the magnetic beads are linked via a peptide. The peptide is N-terminal prohormone brain natriuretic peptide (NT-proBNP), which is a heart failure marker. The efficacy of the two electrochemical assays as a function of the ratio of the two labels was investigated using a galvanic exchange/anodic stripping voltammetry method. The key finding is that by optimizing the ratio of the two types of AgNP labels, it is possible to decrease the LOD of the assays without compromising the dynamic range compared to using either of the two labels independently. This made it possible to achieve the clinically relevant range for NT-proBNP analysis used by physicians for heart failure risk stratification.

Selective modified stripping voltammetric sensor based on Ce-1,4-benzenedicarboxylic metal–organic frameworks porous nanoparticles for picomolar detection of curcumin

• Porous Ce-BDC MOF nanoparticles were fabricated via the solvothermal method. • A modified stripping voltammetric sensor was fabricated with 1.0% Ce-BDC. • The sensor showed remarkable conductivity and electrocatalytic activity. • Low detection limits and a wide linearity range detection of curcumin were measured. • The sensor detected both co-mixed CUR and PIP concentrations without interference. A modified stripping voltammetric sensor based on porous nanoparticles from a Ce-1,4-benzenedicarboxylic (Ce-BDC) metal–organic framework (MOF) has been successfully fabricated for the detection of curcumin (CUR). Fabrication of porous nanoparticles of Ce-BDC acid MOF was carried out via the solvothermal method. The resulting MOF emerges with good crystallinity, octahedral-like morphology, and a specific surface area of 1020 m 2 g −1 , leading to an increase in reaction sites for the sensorand further enhanced performance. Cyclic voltammetry measurements utilizing 1.0% Ce-BDC–modified graphite paste sensor (MGPS) demonstrated a remarkable improvement in electrocatalytic activity and adsorption performance. Under standard detection conditions, the MGPS possessed a low limit of detection of 6 pM and wide linearity ranges of 0.02–2.0 (6.67 μA·nM −1 ) and 2.0–9.0 nM(1.65 μA·nM −1 ) for CUR using the square wave anodic stripping voltammetry method. Furthermore, the MGPS reveals proper accuracy, reproducibility, and storage stability, as well as anti-interference ability during the detection of CUR in biological fluids. The modified stripping voltammetric sensor was able to detect both co-mixed CUR and piperine concentrations, without interference during the analysis process.

Electrochemical Determination of Capsaicinoids Content in Soy Sauce and Pot-Roast Meat Products Based on Glassy Carbon Electrode Modified with Β-Cyclodextrin/Carboxylated Multi-Wall Carbon Nanotubes

The rapid quantification of capsaicinoids content is very important for the standardization of pungent taste degree and flavor control of soy sauce and pot-roast meat products. To rapidly quantify the capsaicinoids content in soy sauce and pot-roast meat products, an electrochemical sensor based on β-cyclodextrin/carboxylated multi-wall carbon nanotubes was constructed and the adsorptive stripping voltammetry method was used to enrich samples in this study. The results showed that the excellent performance of the established electrochemical sensor was mostly because β-cyclodextrin caused the relative dispersion of carboxylated multi-wall carbon nanotubes on the glassy carbon electrode surface. Capsaicin and dihydrocapsaicin had similar electrochemical behavior, so the proposed method could determine the total content of capsaicinoids. The linearity of capsaicinoids content was from 0.5 to 100 μmol/L and the detection limit was 0.27 μmol/L. The recovery rates of different capsaicinoids content were between 83.20% and 136.26%, indicating the proposed sensor could realize trace detection of capsaicinoids content in sauce and pot-roast meat products. This work provides a research basis for pungent taste degree standardization and flavor control in the food industry.

New Screen-Printed Carbon Sensor for Trace Analysis of Thallium(I)

Thallium is an element classified as a heavy metal. In chemical compounds it occurs on +1 and +3 oxidation levels. In the context of the toxicity of this element, Tl(I) is most often referred to. The similarity of Tl+ ions to K+ ions is the basis of the mechanism of toxic action of Tl(I) on the human body. The main features of thallium poisoning in humans are gastroenteritis, polyneuropathy and alopecia Thallium in the environment comes from both natural and anthropogenic sources. Due to the high toxicity of thallium and its easy absorption by the human and animal organisms, it is extremely important to monitor the amount of this element, including in water. The purpose of this work is to present a new method for determination of thallium in water samples using a screen-printed sensor with carbon working electrode modified with multiwalled carbon nanotubes and in-situ plated bismuth film. The measurements were carried out using square wave anodic stripping voltammetry (SWASV) method. Simultaneous deposition of bismuth and thallium took place at a potential of -0.9 V for 180 s. Under optimized conditions a linear calibration curve was obtained in the range of Tl(I) concentrations from 1·10-8 to 1·10-6 mol L-1. The procedure allows to achieve the limits of detection and quantification of Tl(I), 2.8 × 10-9 and 9.3 × 10-9 mol L-1 respectively. The method was applied for determination of Tl(I) in spiked water samples from Vistula river. [1] Kozak, J., Tyszczuk-Rotko, K., Rotko, M. Physicochemical Problems of Mineral Processing 2019 , 55(6), 1422-1428.

Application of ural glauconite for groundwater deironing and demanganation

Heavy metals are among the most common pollutants affecting biological systems when ingested with drinking water and food. Heavy metal ions are capable of bioaccumulation in a human body and could cause various metabolic disorders. Here we present the results of using a unique glauconite from the Barguzinsky deposit as an adsorbent for heavy metals. The physicochemical properties of glauconite samples, including the specific surface area, specific pore volume, zeta potential, thermal and elemental analyses and scanning electron microscopy of the surface were studied for different fraction sizes. The sorption properties of the glauconite samples were studied under static conditions for extraction of iron and manganese ions from model solutions. Analysis of the content of the detected ions in solutions and filtrates was performed by the methods of stripping voltammetry. We revealed high sorption properties of glauconite for iron elimination, but comparatively lower ones in removing manganese.

Preparation of a New Copper/Mercury‐Based Amalgam Electrode with Minimal Mercury Content and Its Application for the Determination of Azathioprine in Biological Fluids

AbstractHerein, a new copper/mercury‐based amalgam electrode with 45 wt % copper was introduced. An amalgam electrode with the lowest mercury content among all amalgam electrodes, reported so far,was introduced. The method of making and activating the electrode was investigated and the working conditions were established. The as‐prepared electrode was employed to determine azathioprine(Aza) using differential pulse adsorptive stripping voltammetry (DPASV) method. The required factors were considered for the electrode voltammetric response to evaluate and optimize Aza level. The proper response of this electrode was obtained in Brinton‐Robinson buffer(BRB) (pH 2) at −0.15 V for 200 seconds. The electrode response to the target compound was linear in the concentration range from 0.04 to 1.0 μM. The detection limit was found to be about 1.6×10−8 M. The relative standard deviation (RSD) for 5 determinations was obtained to be about 3.5 % (the average of RSDs calculated for all concentrations, represented in the calibration curve). The method was successfully applied for Aza determination in plasma and urine samples which led to satisfactory results. It can be concluded that the presence of high levels of potential interfering agents such as ascorbic acid and cysteine did not affect the Aza determination.

Electrochemical Determination of Uric Acid in Urine by Using Zeolite Imidazolate Framework-11 Modified Electrode

In the present article, the synthesis of zeolite imidazole framework-11 (ZIF-11) by ultrasonic-assisted hydrothermal process and its application as an electrode modifier for electrochemical determination of uric acid in urine are demonstrated. The obtained materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and nitrogen adsorption/desorption isotherms. It was found that the ZIF-11 with rhombic dodecahedron topology and high surface area (1066 m2.g-1) was synthesized in a certain temperature and found in around 25–40°C, and other crystalline phases of zinc benzimidazolate deferring from ZIF-11 phase were found in less 25°C or higher than 40°C. The ZIF-11 is stable in the pH range 6-10. The modification of glassy carbon electrode was performed with ZIF-67 using the drop-casting procedure. The present ZIF-11 modified electrode was employed to study the electrochemical behavior of uric acid (UA). UA oxidation is catalyzed by this electrode in aqueous buffer solution (pH 7) with a decrease of 70 mV in overpotential compared to glassy carbon electrode. With the differential pulse–anodic stripping voltammetry (DP-ASV) method, the oxidation current of UA versus its concentration shows good linearity in the range 20–540μM ( R = 0.998 ) with a detection limit of 0.48 μM ( S / N = 3 ). The obtained ZIF-11 modified electrode was applied in the detection of UA content in urine samples, and satisfied results were obtained.

The Development of a Multisensory Stripping Voltammetry Method for the Analysis of Medical Preparations: Determination of Fentanyl in Lacrimal Fluid

The Development of a Multisensory Stripping Voltammetry Method for the Analysis of Medical Preparations: Determination of Fentanyl in Lacrimal Fluid

Effect of Serum on Electrochemical Detection of Bioassays Having Ag Nanoparticle Labels.

The effect of serum on electrochemical detection of bioassays having silver nanoparticle (AgNP) detection labels was investigated. Both a model assay and an antigen-specific sandwich bioassay for the heart failure marker NT-proBNP were examined. In both cases, the AgNP labels were conjugated to a detection antibody. Electrochemical detection was carried out using a galvanic exchange/anodic stripping voltammetry method in which Au3+ exchanges with AgNP labels. The assays were carried out using a paper-based electrode platform. The bioassays were exposed to different serum conditions prior to and during detection. There are three important outcomes reported in this article. First, both the model- and antigen-specific assays could be formed in undiluted serum with no detectable interferences from the serum components. Second, to achieve the maximum possible electrochemical signal, the highest percentage of serum that can remain in an assay buffer during electrochemical detection is 0.25% when no washing is performed. The assay results are rendered inaccurate when 0.50% or more of serum is present. Third, the factors inhibiting galvanic exchange in serum probably relate to surface adsorption of biomolecules onto the AgNP labels, chelation of Au3+ by serum components, or both. The results reported here provide general guidance for using metal NP labels for electrochemical assays in biofluids.

Comparative analysis of methods of photoelectric colorimetry and stripping voltammetry in assessing the content of arsenic in sea bass samples

The development of effective algorithms for optimizing the laboratory equipment base is one of the urgent tasks. Arsenic is classified as a toxicant of the highest hazard group; it is a highly toxic cumulative poison with a broad spectrum of action. The paper considers an assessment of the method for investigating the content of arsenic in sea bass. The research results (by the methods of photoelectric colorimetry and stripping voltammetry) on the operational control of the error using the method of additions and the assessment of the precision were found to be satisfactory. The monitoring results are presented, namely the results indicate that in the range from 0.02 to 0.05 mg of arsenic per 1 kg of sea bass, k prevails (28.1%) over other ranges. The least registered sample results (20.8%) with a range of obtained data are less than 0.02 mg/kg.

Results of comparative research methods for arsenic content in meat samples of broiler chickens

The development of effective algorithms for optimizing the laboratory equipment base is one of the urgent tasks. Arsenic is classified as a toxicant of the highest hazard group; it is a highly toxic cumulative poison with a broad spectrum of action. The paper considers an assessment of the method for researching the content of arsenic in meat and meat products. The results of investigations (by the methods of photoelectric colorimetry and stripping voltammetry) on the operational control of the error using the method of additions and the assessment of precision were recognized as satisfactory. Comparative analysis of two methods of photoelectric colorimetry and stripping voltammetry in assessing the content of arsenic in samples of broiler chicken meat showed their relevance in the development of laboratory practice. 45.2%) over other ranges. The least registered sample results (1.1%) with the range of obtained data - 0.1-1.0 mg/kg.

Condition Assessment Industrially Contaminated Soils of Kuzbass by Bioindication

This work evaluates the state of the soil that has undergone negative changes as a result of technogenic impacts, the presence of pollutants - heavy metals, considers the assessment of the state of the soil by the bioindication method. Shell amoebae, which are unicellular organisms, as well as earthworms and plants, were used as bioindicators. We also studied the ratio of the concentration of heavy metals in the soil to the distance of these soils from the source of heavy metals, and the seasonal dynamics of changes in the content of heavy metals in the soil. Using the method of stripping voltammetry, results were obtained on the presence of heavy metals in soil, earthworms and plants.

Monitoring the stability of the results of studies of chilled river fish for cadmium content using the method of additions

The results obtained indicate that in the range of less than 0.01 mg of cadmium per 1 kg of river fish prevails (43.3%) over other ranges. The least registered sample results (4.3%) with the range of obtained data - 0.1-1.0 mg/kg. The relevance of the problem under consideration is due to the need to encompass a broad spectrum in the determination of cadmium in river fish in hardware. The primary and important task remains to ensure control of the quantitative content of cadmium, the introduction and application of fast and reliable methods of their research. The analysis of the data obtained shows that all the results on the study of chilled river fish for the content of cadmium, obtained by the methods of stripping voltammetry and atomic absorption spectrometry, to assess the precision and operational control of the error using the method of additions are satisfactory. The implementation of the methods of stripping voltammetry and atomic absorption spectrometry achieves the best precision of research results in the testing laboratory, both under repeatability conditions and under conditions of intermediate precision.

Evaluation of the stability of the results of studies of beef for lead content using the additive method

The obtained monitoring results indicate that in the range of less than 0.01 mg of lead per 1 kg of beef prevails (51.9%) over other ranges. The least registered sample results (3.4%) with the range of obtained data - 0.1-1.0 mg / kg. The primary and important task remains to ensure the control of the quantitative content of lead, the introduction and application of fast and reliable methods of their research. The analysis of the obtained data results shows that all the results on the study of beef for the content of lead, obtained by stripping voltammetry and atomic absorption spectrometry methods for assessing the precision and operational control of the error using the additive method, are satisfactory. By implementing the methods of stripping voltammetry and atomic absorption spectrometry, the best precision of research results in the testing laboratory is achieved, both under repeatability conditions and under conditions of intermediate precision.

Control of the stability of the results of studies of cadmium content using the method of additions in cow’s milk samples

The relevance of the problem under consideration is due to the need to use hardware to cover a wide range in the determination of toxic elements (heavy metals) in food. The primary and important task is to ensure control of the quantitative content of cadmium, the introduction and application of fast and reliable methods of their research. The analysis of the data obtained shows that all the results on the study of milk for the content of cadmium, obtained by stripping voltammetry and atomic absorption spectrometry by assessing the precision and operational control of the error using the method of additions, are satisfactory. The implementation of the methods of stripping voltammetry and atomic absorption spectrometry achieves the best precision of research results in the testing laboratory, both under repeatability conditions and under conditions of intermediate precision. The results obtained indicate that in the range of less than 0.01 mg of cadmium per 1 kg of cow’s milk, prevail (42.2%) over other ranges (during monitoring). The least registered sample results are (1.4%) with the range of obtained data - 0.01-0.05 mg/kg.

Ultra-sensitive facile CdS nanocrystals-based electrochemical biosensor to detect myocardial infarction marker troponin

Here, we report on a reproducible one-pot synthesis of high-quality and monodispersed CdS semiconducting nanocrystals (NCs) by mixing precursors cadmium acetate and elemental sulfur into the new solvent system of dibenzyl ether and oleylamine without using any extra reagent or precursor activator. The NCs (5 nm) exhibited a dominant band-edge emission with a good photoluminescence quantum yield of 13.76% without trap emission. The CdS NCs were characterized using UV–Vis and photoluminescence spectroscopy, electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The practical efficiency of the synthesized NCs was proved by applying the synthesized CdS NCs as the tracer in the engineering of an immunosandwich biosensor to evaluate the cardiac troponin (cTn) marker for the diagnosis and monitoring of myocardial infarction (MI). The biosensor revealed significant analytical efficiency with the limit of detection of 2 ng L−1 and the linear dynamic range of 5–1000 ng L−1, which is lower than the existing cutoff values (13–20 ng L−1). Having capitalized on the anodic stripping voltammetry method, the screen-printed biosensor could efficiently detect the cTn markers. Therefore, the biosensor is proposed to be used in clinical settings for fast, sensitive, and accurate monitoring of cTn markers.

Underpotential-deposition synthesis and in-line electrochemical analysis of single-atom copper electrocatalysts

Carbon supported single-atom catalysts (SACs) with well-defined active sites and maximum atom utilization efficiency exhibit good activity and selectivity toward a series of electrocatalytic reactions. For the practical applications of SACs, development of facile synthetic methods and analytical techniques is highly useful. Here, single-atom copper has been successfully anchored on sulfur sites of doped graphite foam via an underpotential deposition strategy. By this strategy, the loading amount of Cu SACs can be regulated through tuning the deposition potential, the S contents of the doped graphite foam and the concentration of Cu precursor; moreover, the regulation is perfectly in line with Nernst equation combined with Langmuir adsorption model. Importantly, a stripping voltammetry method is successfully developed for the first time to in-line quantitatively analyze the resultant Cu SACs. Our Cu SACs exhibit remarkable oxygen reduction reaction (ORR) activity with a half-wave potential of 0.862 V (vs RHE) and long-term stability.

Stripping voltammetry of nanoscale films of Zn–Ni alloy

Nanoscale Zn–Ni alloy films of ~ 20…90 nm thickness were obtained from ammonia-glycinate electrolyte in the potential range from − 1.15 to − 1.475 V. Chemical and phase composition of films were analyzed by stripping voltammetry in alkaline ammonia-glycinate electrolyte. It is shown that the method of stripping-voltammetry in this electrolyte allows estimation of the content of both crystalline and amorphous phases of Zn–Ni alloy, including films with small content of components. All alloy films contain a γ-phase in the mentioned range of potentials. Its maximum content (95%) is observed at a potential of − 1.2 V corresponding to the beginning of the limiting current on the polarization curve of the alloy deposition. Despite the fact that Zn is a more negative metal in the zinc–nickel pair, its content in the alloy decreases with an increase in the polarization of deposition due to anomalous codeposition of Zn with Ni. As the Ni content increases, the contributions of the β-phase and the Ni-phase increase. It is shown that in an electrolyte of the same composition, layers of an alloy of different chemical and phase composition are deposited depending on the potential. Results can be useful both for analyzing the composition of films obtained from other electrolytes, and for choosing the architecture of multilayer coatings deposited by the single-bath method.