scholarly journals New Strategies for the Simple and Sensitive Voltammetric Direct Quantification of Se(IV) in Environmental Waters Employing Bismuth Film Modified Glassy Carbon Electrode and Amberlite Resin

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4130
Author(s):  
Małgorzata Grabarczyk ◽  
Marzena Adamczyk

An analytical procedure regarding the determination of selenium(IV) by anodic stripping voltammetry exploiting the in situ plated bismuth film electrode is described. Since organics are commonly present in untreated natural water samples, the use of Amberlite XAD-7 resin turns out to be quite important to avoid problems such as the adsorption of these compounds on the working electrode. The optimum circumstances for the detection of selenium in water using differential pulse voltammetry techniques were found to be as follows: 0.1 mol L−1 acetic acid, 1.9 × 10−5 mol L−1 Bi(III), 0.1 g Amberlite XAD-7 resin, and successive potentials of −1.6 V for 5 s and −0.4 V for 60 s, during which the in situ formation of the bismuth film on glassy carbon and the accumulation of selenium took place. The current of the anodic peak varies linearly with the selenium concentration ranging from 3 × 10−9 mol L−1 to 3 × 10−6 mol L−1 (r = 0.9995), with a detection limit of 8 × 10−10 mol L−1. The proposed procedure was used for Se(IV) determination in certified reference materials and natural water samples, and acceptable results and recoveries were obtained.

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 279 ◽  
Author(s):  
Samuel Frutos-Puerto ◽  
Conrado Miró ◽  
Eduardo Pinilla-Gil

In this work, we explore the protection with Nafion of commercial sputtered-bismuth screen-printed electrodes (BiSPSPEs), 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 BiSPSPEs in pH = 4.4 medium, and similar or lower detection limits than comparable methods on commercial BiSPSPEs. 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%).


Author(s):  
Katarzyna Domańska ◽  
Katarzyna Tyszczuk-Rotko ◽  
Sabina Dąbal

<p>This paper shows a novel, simple and rapid voltammetric procedure, which enables Cd and Pb determination at traces concentrations. All measurements were carried out by differential  pulse anodic stripping voltammetry (DPASV) with total time of analysis of 210 s. The obtained detection limits were 8.46 · 10<sup>-10</sup> mol L<sup>-1</sup> and 2.57 · 10<sup>-10</sup> mol L<sup>-1</sup>  for Cd(II) and Pb(II), respectively. This procedure was successfully applied for the quantification of mentioned metal ions in water samples collected from the Vistula River.</p>


2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Nguyen Thị Hue ◽  
Nguyen Van Hop ◽  
Hoang Thai Long ◽  
Nguyen Hai Phong ◽  
Tran Ha Uyen ◽  
...  

Development of adsorptive stripping voltammetry (AdSV) combined with in situ prepared bismuth film electrode (in situ BiFE) on glassy carbon disk surface using diethylenetriamine pentaacetic acid (DTPA) as a complexing agent and NO3− as a catalyst to determine the trace amount of chromium (VI) is demonstrated. According to this method, in the preconcentration step at Edep = −800 mV, the bismuth film is coated on the surface of glassy carbon electrodes simultaneously with the adsorption of complexes Cr(III)-DTPA. In addition to the influencing factors, the stripping voltammetry performance factors such as deposition potential, deposition time, equilibration time, cleaning potential, cleaning time, and technical parameters of differential pulse and square wave voltammetries have been investigated, and the influence of Cr(III), Co(II), Ni(II), Ca(II), Fe(III), SO42−, Cl−, and Triton X has also been investigated. This method gained good repeatability with RSD <4% (n = 9) for the differential pulse adsorptive stripping voltammetry (DP-AdSV) and RSD < 3% (n = 7) for the square wave adsorptive stripping voltammetry (SqW-AdSV), and low limit of detection: LOD = 12.10−9 M ≈ 0.6 ppb (at a deposition potential (Edep) of −800 mV and the deposition time (tdep) of 50 s) and LOD = 2.10−9 M ≈ 0.1 ppb (at Edep = −800 mV and tdep = 160 s) for the DP-AdSV and SqW-AdSV, respectively. This method has been successfully applied to analyze chromium in natural water.


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