Simultaneous Determination of Pb and Cd Traces in Water Samples by Anodic Stripping Voltammetry Using a Modified GC Electrode (original) (raw)
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Journal of Electrochemical Science and Engineering, 2019
Glassy carbon electrode (GCE) modified by 2-mercaptobenzothiazole (MBT), mesoporous silica (Meso) and bismuth was developed to determine Cd(II) and Pb(II) simultaneously by square wave anodic stripping voltammetry (SWASV). In-situ preparation was found to work best in optimum conditions of acetate buffer pH 6, accumulation potential of-1.1 V, deposition time of 300 s and scan rate of 200 mV/s. SW peaks revealed the linear range of 5-50 µg/L Cd(II) and 5-50 µg/L Pb(II). LOD and LOQ for Cd(II) and Pb(II) were determined as 0.56, 0.80, 1.87 and 2.66 µg/L, respectively. The interaction of metals with bismuth and MBT, as well as higher surface area due to mesoporous silica, support beneficial performance of the modified electrode. Insignificant interferences from other regularly present metal ions were found. With SRM1640 standard, the SWASV results are found comparable to those obtained by inductive coupled plasma optical emission spectrometry (ICP-OES). The method was used to analyze the metals in tap water by standard addition method with the satisfactory recovery of 100.7 % for Cd(II) and 100.8 % for Pb(II).
Journal of Electroanalytical Chemistry, 2010
This work describes a novel type of renovated silver ring electrode (RSRE), as mercury-free sensor, for anodic stripping voltammetry (ASV). The great advantages of the RSRE are simplicity, periodic renovation of the surface and the possibility of repetitive measurements on the surface completely free from reaction products, adsorbed surface-active species, etc. The sensor was tested for the detection of nanomolar concentrations of Pb 2+ and Cd 2+ by ASV in water samples without removal of oxygen and surfactants. Detection limits of 0.5 nM for Pb 2+ and 2 nM for Cd 2+ have been achieved following 60 s electrodeposition. The validation of the proposed RSRE was made by Pb 2+ and Cd 2+ determination using the certified reference materials (Surface Waters). The RSRE was successfully applied to Pb 2+ and Cd 2+ analysis in tap water and to river water with a high content of organic contaminants.
Sensors, 2019
In this work, we explore the protection with Nafion of commercial sputtered-bismuth screen-printed electrodes (Bi SP SPEs), to improve its ability for on-site determination of Cd(II) and Pb(II) ions in ambient water samples. The modified screen-printed platform was coupled with a miniaturized cell, in combination with a battery-operated stirring system and a portable potentiostat operated by a laptop for decentralized electrochemical measurements using Square-Wave Anodic Stripping Voltammetry (SWASV). We also describe a detailed electrode surface characterization by microscopy and surface analysis techniques, before and after the modification with Nafion, to get insight about modification effect on signal size and stability. Optimization of the chemical composition of the medium including the optimization of pH, and instrumental parameters, resulted in a method with detection limits in the low ng/mL range (3.62 and 3.83 ng·mL −1 for Cd and Pb respectively). Our results show an improvement of the sensitivity and stability for Nafion-protected Bi SP SPEs in pH = 4.4 medium, and similar or lower detection limits than comparable methods on commercial Bi SP SPEs. The values obtained for Pb(II) and Cd(II) in natural water samples agreed well with those obtained by the much more costly Inductively Coupled Plasma Mass Spectrometry, ICP-MS, technique as a reference method (recoveries from 75% to 111%).
Electroanalysis, 2014
A method using commercially available sputtered bismuth screen-printed electrodes (Bi sp SPE), as substitute to mercury electrodes, for the determination of trace Pb(II) and Cd(II) ions in drinking well water samples collected in a contaminated area in The Republic of El Salvador by means of differential pulse anodic stripping voltammetry (DPASV) has been proposed. The comparable detection and quantification limits obtained for both Bi sp SPE and hanging mercury drop electrode (HMDE), together with the similar results with a high reproducibility obtained in these water samples analyses recommend the applicability of Bi sp SPE for the determination of low level of metal concentrations in natural samples.
Analytica Chimica Acta, 1982
We report on a glassy carbon electrode modified with bismuth nanoparticles (NanoBiE) for the simultaneous determination Pb 2+ and Cd 2+ by anodic stripping voltammetry. Operational parameters such as bismuth nanoparticles labelling amount, deposition potential, deposition time and stripping parameters were optimized with respect to the determination of Pb 2+ and Cd 2+ in 0.1 M acetate buffer solution (pH 4.5). The NanoBiE gives well-defined, reproducible and sharp stripping peaks. The peak current response increases linearly with the metal concentration in a range of 5.0-60.0 μg L −1 , with a detection limit of 0.8 and 0.4 μg L −1 for Pb 2+ and Cd 2+ , respectively. The morphology and composition of the modified electrode before and after voltammetric measurements were analysed by scanning electron microscopy and energy dispersive X-ray analysis. The NanoBiE was successfully applied to analysis of Pb 2+ and Cd 2+ in real water samples and the method was validated by ICP-MS technique, suggesting that the electrode can be considered as an interesting alternative to the bismuth film electrode for possible use in electrochemical studies and electroanalysis.
International Journal of Environmental Analytical Chemistry, 2019
In this study, we demonstrated a highly sensitive electrochemical sensor for the simultaneous detection of Pb (II) and Cd (II) in aqueous solution using carbon paste electrode modified with Eichhornia crassipes powder by square wave anodic stripping voltammetry. The effect of modifier composition, pH, preconcentration time, reduction potential and time, and type of supporting electrolyte on the determination of metal ions were investigated. Pre-concentration on the modified surface was performed at open circuit. The modified electrode exhibited well-defined and separate stripping peaks for Pb (II) and Cd (II). Under optimum experimental conditions, a linear range for both metal ions was from 10 to 5000 μg L −1 with the detection limits of 4.9 μg L −1 , 2.1 μg L −1 for Cd(II) and Pb (II), respectively. The modified electrode was found to be sensitive and selective when applied to determine trace amounts of Cd (II) and Pb (II) in natural water samples.
Analytical and bioanalytical chemistry, 2017
A simple and rapid analytical method of determining Pb(2+) and Cd(2+) in water samples using an electrochemically pretreated pencil-graphite electrode (EP-PGE) is proposed for the first time in the literature. An electrochemically pretreated pencil-graphite electrode was prepared by performing potential cycling between -0.3 V and 2.0 V in 0.1 mol L(-1) H3PO4 solution to improve its ability to electrochemically sense Pb(2+) and Cd(2+) ions. Square-wave anodic stripping voltammetry (SWASV) was used as the electroanalytical method. The electroanalytical parameters that influence the stripping determination of Pb(2+) and Cd(2+) were optimized based on experimental results. The magnitude of the peak oxidation current was adjusted in order to optimize the value of each parameter. Applying the resulting disposable electrode under the optimized conditions led to good selectivity and sensitivity in the determination of Pb(2+) and Cd(2+) ions. Interference from coexisting ions was also invest...
Scienceasia, 2010
A simple and rapid method to determine traces of lead in the Hatyai city tap water by square wave anodic stripping voltammetry with boron-doped diamond (BDD) electrode has been studied. The parameters in the preconcentration steps studied included electrolyte influences, pH, concentrations, and volumes. Effective preconcentration of trace lead was achieved at pH 1.26. The appropriate electrolyte was found to be 0.2 M potassium nitrate (KNO3) in 0.05 M nitric acid (HNO3) to make all lead ionic. By scanning potential in the negative direction, the stripping peak was obtained at 0.460 V. Instrumental parameters including deposition potential, deposition time, scan rate, modulation amplitude, and equilibration time were optimized. The detection limit was found to be 0.3 µg/l. The accuracy was verified by analysing the standard reference material. Several interfering ions were studied and it was found that the method was not significantly affected by these coexisting ions and can be appl...