Stripping Voltammetric Determination Of Pb Research Articles

A new modified carbon paste electrode using N1-hydroxy-N1,N2-diphenylbenzamidine for the square wave anodic stripping voltammetric determination of Pb(II) in environmental samples

This study presents a new method for simple, selective and sensitive electrochemical determination of lead(II) using N1-hydroxy-N1,N2-diphenylbenzamidine (HDPBA) modified carbon paste electrode. HDPBA was easily prepared in the laboratory from common chemicals. Morphological characterizations and spectroscopic analyses of the developed electrode were conducted using various analytical techniques such as electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), Fourier transform infrared (FTIR), and ultraviolet-visible (UV–Vis) spectroscopic techniques. The electrochemical determination of Pb(II) was performed using square wave anodic stripping voltammetry (SWASV) and cyclic voltammetry (CV). The effects of several experimental parameters such as modifier composition in the carbon paste, composition and pH of supporting electrolyte solutions, accumulation time, accumulation potential, and other instrumental parameters were studied for the analytical application. Pb(II) was accumulated for 270 s on the surface of the modified electrode using 0.1 M sodium acetate (NaAc) pH 5 at −0.90 V vs Ag/AgCl, followed by electrochemical stripping with SWASV in the same solution after a resting time of 10 s. The linear range was found to be 0.0001–2.5000 μM Pb(II) with a limit of detection of 0.0094 nM which are better than most of the reported method based on 2–4 different modifiers in a single electrode. The proposed method was found to be highly sensitive and selective. In addition, the developed electrode showed good reproducibility (with RSDs of 4.3%), long-term stability, and fast response. The proposed method has been successfully applied to the determination of trace levels of Pb(II) in various environmental samples such as wastewater, vegetable, fish, and cigarette samples.

A polyrutin/AgNPs coated GCE for simultaneous anodic stripping voltammetric determination of Pb(II) and Cd(II)ions in environmental samples

Here, we report a simple one-step preparation of polyrutin/silver nanoparticles (AgNPs) on the glassy carbon electrode (GCE) surface using an electrochemical deposition/polymerization technique. As prepared polyrutin/AgNPs/GCE has been characterized by different techniques such as SEM with elemental morphing, TEM with EDAX, XRD, ATR-IR to confirm the materials formation. Further, electrochemical behavior of the polyrutin/AgNPs/GCE was tested by cyclic voltammetry, EIS and differential pulse voltammetric techniques. As fabricated polyrutin/AgNPs/GCE was used for simultaneous detection of Pb(II) and Cd(II)ions using anodic stripping voltammetric techniques and stripping analysis of Pb(II) and Cd(II)ions analytical parameters like pH, preconcentration time were studied. The polyrutin/AgNPs/GCE has showed a linear concentration range from 29 nM to 140 nM and 57–203 nM with detection limit of 3 nM and 10 nM for Pb(II) Cd(II)ions respectively. Further, the modified electrode was tested towards detection of these heavy metal ions in different environmental samples and the found excellent recovery results were further correlated with ICP-MS results.

Green Synthesis of Ag Nanoparticles Using Grape Stalk Waste Extract for the Modification of Screen-Printed Electrodes.

The chemical synthesis of silver nanoparticles (Ag-NPs) by using an environmentally friendly methodology for their preparation is presented. Thus, considering that plants possess components that can act as reducing agents and stabilizers in nanoparticles’ production, the synthesis of Ag-NPs by using an extract aqueous solution of grape stalk waste as a reducing and capping agent is studied. First, the total polyphenols and reducing sugars contained in the produced extracts at different conditions are characterized. After that, Ag-NPs are synthesized regarding the interaction of Ag ions (from silver nitrate) and the grape stalk extract. The effect of temperature, contact time, extract/metal solution volume ratio and pH solution in the synthesis of metal nanoparticles are also studied. Different sets of nanoparticle samples are characterized by means of Electron Microscopy coupled with Energy Dispersive X-Ray for qualitative chemical identification. Ag-NPs with an average diameter of 27.7 ± 0.6 nm are selected to proof their suitability for sensing purposes. Finally, screen-printed electrodes modified with Ag-NPs are tested for the simultaneous stripping voltammetric determination of Pb(II) and Cd(II). Results indicate good reproducibility, sensitivity and limits of detection around 2.7 µg L−1 for both metal ions.

A mercury free electrode for anodic stripping voltammetric determination of Pb (II) ions using poly zincon film modified electrode

With an aim of developing a mercury-free electrode for anodic stripping voltammetric determination of Pb (II) ions, a poly zincon film (PZF) modified electrode is reported here. The PZF on the electrode surface has been obtained by electropolymerisation of zincon. PZF present on the electrode surface has been used for preconcentrating Pb (II) ions through complexation. The electrochemical determination of the above metal ion has been carried out by reducing the preconcentrated Pb (II) at −1.0V followed by anodic stripping in acetate buffer of pH 6 and measuring the stripping current at −0.64V. The PZF and Pb preconcentrated PZF modified electrodes have been characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The factors influencing the determination of Pb (II) ions such as the nature of medium/background electrolyte, pH, preconcentration time and electrode regeneration have been studied in detail. Under optimum conditions, a linear relation for the stripping current with Pb (II) ions in the solution has been observed in the range from 3.45 to 136.3μgL−1 with a detection limit of 0.98μgL−1. The regeneration of the modified electrode after each experiment has been achieved by simply immersing the electrode in 0.1M EDTA solution for 2min and washing thoroughly in de-ionised water. PZF modified electrode has shown a promising and sensitive platform for the anodic stripping determination of Pb (II) ions and the regeneration of the electrode has been found to be easy for subsequent uses. The proposed method has been applied for the determination of Pb (II) ions in ground water and tap water samples.

Differential Pulse Anodic Stripping Voltammetric Determination of Lead (II) Using Poly Xylenol Orange Modified Electrode

AbstractIn this work a method for sensitive anodic stripping voltammetric determination of Pb(II) ions using a poly xylenol orange film modified electrode (PXOFME) has been proposed. Poly xylenol orange film (PXOF) was formed on a paraffin impegrenated graphite electrode (PIGE) using electro polymerization method by scanning the potential between −0.5 V to 1.3 V, at a scan rate of 50 mV/s for 30 segments in 0.1 M phosphate buffer solution (PBS) of pH 7. The PXOFME was characterized by scanning electron microscopy (SEM), ATR‐IR spectroscopy, cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The modified electrode has been used to develop a sensitive method for the determination of Pb(II) ions by anodic stripping voltmmetry (ASV). The PXOFME was used to preconcentrate Pb(II) ions through complexation, the complexed metal ions were reduced electrochemically and then stripped anodically from the surface of the electrode. A linear range of 5 μg/L to 413 μg/L with a limit of detection (S/N=3) of 1.6 μg/L was observed for the determination of Pb(II) ions. The method was applied to lead determination in sea water and tap water samples and the results were found to be satisfactory.

One-step synthesis of isoreticular metal–organic framework-8 derived hierarchical porous carbon and its application in differential pulse anodic stripping voltammetric determination of Pb(ii)

A novel electrochemical sensor for Pb(ii) was constructed based on an IRMOF-8-derived NPC with three-dimensional hierarchy of micro-, meso-, and macropores (BET surface area = 1715 m2 g−1).

Simultaneous Anodic Stripping Voltammetric Determination of Pb and Cd, Using a Vibrating Gold Microwire Electrode, Assisted by Chemometric Techniques

AbstractSimultaneous anodic stripping voltammetric determination of Pb and Cd is restricted on gold electrodes as a result of the overlapping of these two peaks. This work describes the quantitative determination of a binary mixture system of Pb and Cd, at low concentration levels (up to 15.0 and 10.0 µg L−1 for Pb and Cd, respectively) by differential pulse anodic stripping voltammetry (DPASV; deposition time of 30 s), using a green electrode (vibrating gold microwire electrode) without purging in a chloride medium (0.5 M NaCl) under moderate acidic conditions (HCl 1.0 mM), assisted by chemometric tools. The application of multivariate curve resolution alternating least squares (MCR‐ALS) for the resolution and quantification of both metals is shown. The optimized MCR‐ALS models showed good prediction ability with concentration prediction errors of 12.4 and 11.4 % for Pb and Cd, respectively. The quantitative results obtained by MCR‐ALS were compared to those obtained with partial least squares (PLS) and classical least squares (CLS) regression methods. For both metals, PLS and MCR‐ALS results are comparable and superior to CLS. For Cd, as a result of the peak shift problem, the application of CLS was unsuitable. MCR‐ALS provides additional advantage compared to PLS since it estimates the pure response of the analytes signal. Finally, the built up multivariate calibration models, based either in MCR‐ALS or PLS regression, allowed to quantify concentrations of Pb and Cd in surface river water samples, with satisfactory results.

A glassy carbon electrode modified with antimony and poly(p-aminobenzene sulfonic acid) for sensing lead(II) by square wave anodic stripping voltammetry

We have developed a sensor for the square wave anodic stripping voltammetric determination of Pb(II). A glassy carbon electrode was modified with a thin film of an antimony/poly(p-aminobenzene sulfonic acid) composite in air-saturated aqueous solution of pH 2.0. Compared to a conventional antimony film electrode, the new one yields a larger stripping signal for Pb(II). The conditions of polymerization, the concentration of Sb(III), the pH value of the sample solution, the deposition potential and time, frequency, potential amplitude, and step increment potential were optimized. Under the optimum conditions, a linear response was observed for Pb(II) in the range of 0.5 to 150.0 μg L−1. The detection limit for Pb(II) is 0.1 μg L−1.

Square wave anodic stripping voltammetric determination of lead(II) using a glassy carbon electrode modified with a lead ionophore and multiwalled carbon nanotubes

We report on a glassy carbon electrode (GCE) modified with a lead ionophore and multiwalled carbon nanotubes. It can be applied to square wave anodic stripping voltammetric determination of Pb(II) ion after preconcentration of Pb(II) at −1.0 V (vs. SCE) for 300 s in pH 4.5 acetate buffer containing 400 μg L−1 of Bi(III). The ionophore-MWCNTs film on the GCE possesses strong and highly selective affinity for Pb(II) as confirmed by quartz crystal microbalance experiments. Under the optimum conditions, a linear response was observed for Pb(II) ion in the range from 0.3 to 50 μg L−1. The limit of detection (at S/N = 3) is 0.1 μg L−1. The method was applied to the determination of Pb(II) in water samples with acceptable recovery.

Multiwalled carbon nanotube modified with 1-(2-pyridylazo)-2-naphthol for stripping voltammetric determination of Pb(ii)

The present work is focused on the modification of multiwalled carbon nanotubes with a ligand, 1-(2-pyridylazo)-2-naphthol (PAN), and its potential application for the development of a new, simple and selective modified glassy carbon electrode for stripping voltammetric determination of Pb(II). The electrochemical method is based on closed circuit accumulation of lead ions onto a PAN-modified multiwalled carbon nanotube electrode from 0.1 mol L(-1) oxalate buffer solution (pH = 3.0) during 150 s at the potential of -0.9 V, following by differential pulse anodic stripping voltammetric determination in the range -0.9 to -0.35 V. The analytical curve for Pb(II) ions covers a linear range varying from 0.8 up to 220.4 microg L(-1). The limit of detection was found to be 0.1 microg L(-1), while the relative standard deviation (RSD) at 50.0 microg L(-1) was 1.8% (n = 5). Many of the coexisting ions had little or no effect on the determination of lead(II). The results suggest that the proposed method can be applied as a simple and efficient alternative technique for the determination of lead ions which has good accuracy in real samples such as natural waters and standard alloys. In addition, this method demonstrates the powerful application of carbon nanotubes in the field of mercury-free electrodes in voltammetric stripping analysis.

Combining orthogonal signal correction and wavelet packet transform with radial basis function neural networks for multicomponent determination

This paper presented a novel method named OSCWPTRBFN based on the concept of data mining in chemometrics for resolving overlapping spectra. The method combines orthogonal signal correction, wavelet packet transform and radial basis function neural network for enhancing the ability of removing noise and eliminating unrelated information as well as improving the quality of the regression method. OSC was applied to remove structured noise that is unrelated to the concentration variables. Wavelet packet representations of signals provided a local time–frequency description, thus in the wavelet packet domain, the quality of noise removal can be improved. Radial basis function network was applied for overcoming the convergence problem met in back propagation training and for facilitating nonlinear calculation. In this spectrophotometric case, through optimization, the number of OSC components, wavelet function, decomposition level, the number of hidden nodes and the width ( σ) of RBFN for OSCWPTRBFN method were selected as 1, Coif 2, 4, 15 and 0.7 respectively. The relative standard errors of prediction (RSEP) for all components with OSCWPTRBFN, WPTRBFN, RBFN, partial least squares (PLS), OSCWPTPLS, principal component regression (PCR), Fourier transform based PCR (FTPCR) and multivariate linear regression (MLR) methods were 6.85, 7.74, 22.0, 10.1, 8.93, 13.5, 13.1, and 2.38 × 10 3% respectively. Experimental results showed that the OSCWPTRBFN method was successful and had advantages over the other approaches. The results obtained from an additional test case, simultaneous differential pulse stripping voltammetric determination of Pb(II), Cd(II) and Ni(II), also demonstrated that the OSCWPTRBFN method performed very well.

Square wave anodic stripping voltammetric determination of Pb 2+ using acetylene black paste electrode based on the inducing adsorption ability of I −

Herein, a sensitive and simplified electrochemical method was proposed for the determination of trace levels of Pb 2+ by anodic stripping voltammetry (ASV) based on the inducing adsorption ability of I − toward Pb 2+. In the presence of low concentration of I −, Pb 2+ was induced to accumulate onto the acetylene black (AB) paste electrode surface, and then reduced at −0.90 V. During the following square wave sweep from −0.90 to −0.30 V, the reduced Pb was oxidized, resulting in a sensitive and well-shaped stripping peak at −0.56 V. Further studies indicate that low concentration of I − significantly enhances the sensitivity of determination of Pb 2+. After all the experimental parameters were optimized, a novel and sensitive method was developed for the electrochemical determination of Pb 2+. The linear range is found to be from 2.0 × 10 −8 to 4.0 × 10 −6 mol L −1, and the lowest detectable concentration is estimated to be 6.0 × 10 −9 mol L −1. This newly proposed method was finally demonstrated with water samples. Otherwise, the anodic stripping responses of Pb 2+ on AB paste electrode and graphite paste electrode were compared.

Differential Pulse Anodic Stripping Voltammetric Determination of Pb, Cd, Cu, and Zn in Air, Diet, and Blood Samples: Exposure Assessment

Concentrations of heavy metals such as Pb, Cd, Cu, and Zn have been determined by using differential pulse anodic stripping voltammetry (DPASV) in air particulates, diet, and children's blood residing at different locations of Tirupati. The reliability of the procedure for estimation of Pb, Cd, Cu, and Zn in environmental and biological samples by DPASV technique was checked by analyzing various standard reference materials. The observed daily intake of Pb, Cd, Cu, and Zn by children varies from 0.1014 to 0.3264, 0.0204 to 0.0372, 0.1953 to 0.3310, and 76.1902 to 78.3720 µg day−1 through inhalation, and 17.53 to 20.91, 1.92 to 2.32, 954.92 to 1264.70, and 5750.14 to 6774.56 µg day−1 through dietary intake, respectively. Retention times of Pb, Cd, Cu, and Zn in children's blood are estimated by using levels of these metals in air particulates and by duplicating diet and blood of children. The observed average retention times for Pb, Cd, Cu, and Zn are 17.32, 7.85, 2.12, and 1.92 days, respectively.