Detection of Cadmium using Conjugated Polymer Modified Electrodes

2012 ◽  
Vol 1436 ◽  
Author(s):  
Timothy Ponrathnam ◽  
Seth Robertson ◽  
Junghwan Cho ◽  
Pradeep Kurup ◽  
Ramaswamy Nagarajan

ABSTRACTThe detection of heavy metals in subsurface strata currently requires tedious sampling procedures followed by laboratory analysis using techniques such as atomic absorption spectroscopy (AAS) or inductively couple plasma atomic emission spectroscopy (ICP-AES). These techniques are extremely accurate and capable of detecting very low concentrations of metal ions. The main drawback of these techniques is that they are time consuming, expensive to perform and not portable. A portable sensor capable of detecting metals ion in solution is highly desirable. Anodic Stripping Voltammetry (ASV) can be utilized as a reliable method for the trace detection of metal ions in water. In order to improve the sensitivity of the electrochemical sensor, conjugated polymer films can be coated on the surface of the glassy carbon working electrodes. Stable films of poly (3,4 ethylenedioxythiophene) [PEDOT] and polythiophene copolymer [PTCPTA] were electrochemically synthesized on the surface of a glassy carbon electrode. These polymer modified electrodes were utilized for the detection of cadmium in water. The sensors are capable of detecting trace concentrations of cadmium approaching the maximum contamination limits imposed by the Environment Protection Agency (EPA).

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>


Author(s):  
Jongte Lalmalsawmi ◽  
Diwakar Tiwari

Abstract Micro-pollutants, especially antibiotics contamination in water bodies, are a serious concern, and their detection at a low level is important for human health and even aquatic life at large. The present investigation aims to obtain the novel nanocomposite material precursor to clay and silane. The nanocomposite material is decorated with Ag or Au nanoparticles as obtained indigenously by a green route using natural phytochemicals. The materials were extensively characterized by advanced analytical methods. The nanocomposite materials (Ag(NP)/TCBN and Au(NP)/TCBN) are employed in the selective and efficient trace measurement of sulfamethoxazole (SMZ) in aqueous solutions using the differential pulse anodic stripping voltammetry. The cyclic voltammetric and electrochemical impedance spectroscopic methods showed an increased electroactive surface area as well as faster electron transfer reactions compared to the glassy carbon electrode (GCE). The DPASV measurements at the concentration range of 0.25 mg/L to 30.0 mg/L showed that the novel nanocomposites provide the LOD of 0.022 and 0.036 mg/L, respectively, for the Ag(NP)/TCBN/GCE and Au(NP)/TCBN/GCE for sulfamethoxazole. Further, the application of the method for the detection of sulfamethoxazole in real water samples resulted in an acceptable recovery percentage of 93.08 to 103.7.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 723
Author(s):  
Kgotla K. Masibi ◽  
Omolola E. Fayemi ◽  
Abolanle S. Adekunle ◽  
Amal M. Al-Mohaimeed ◽  
Asmaa M. Fahim ◽  
...  

This report narrates the successful application of a fabricated novel sensor for the trace detection of endosulfan (EDS). The sensor was made by modifying a glassy-carbon electrode (GCE) with polyaniline (PANI), chemically synthesized antimony oxide nanoparticles (AONPs), acid-functionalized, single-walled carbon nanotubes (fSWCNTs), and finally, the AONP-PANI-SWCNT nanocomposite. The electrochemical properties of the modified electrodes regarding endosulfan detection were investigated via cyclic voltammetry (CV) and square-wave voltammetry. The current response of the electrodes to EDS followed the trend GCE-AONP-PANI-SWCNT (−510 µA) > GCE-PANI (−59 µA) > GCE-AONPs (−11.4 µA) > GCE (−5.52 µA) > GCE-fSWCNTs (−0.168 µA). The obtained results indicated that the current response obtained at the AONP-PANI-SWCNT/GCE was higher with relatively low overpotential compared to those from the other electrodes investigated. This demonstrated the superiority of the AONP-PANI-SWCNT-modified GCE. The AONP-PANI-SWCNT/GCE demonstrated good electrocatalytic activities for the electrochemical reduction of EDS. The results obtained in this study are comparable with those in other reports. The sensitivity, limit of detection (LoD), and limit of quantification (LoQ) of AONP-PANI-SWCNT/GCE towards EDS was estimated to be 0.0623 µA/µM, 6.8 µM, and 20.6 µM, respectively. Selectivity, as well as the practical application of the fabricated sensor, were explored, and the results indicated that the EDS-reduction current was reduced by only 2.0% when interfering species were present, whilst average recoveries of EDS in real samples were above 97%.


Chemosensors ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 107
Author(s):  
Kequan Xu ◽  
Clara Pérez-Ràfols ◽  
Amine Marchoud ◽  
María Cuartero ◽  
Gastón A. Crespo

The widely spread use of the hanging mercury drop electrode (HMDE) for multi-ion analysis is primarily ascribed to the following reasons: (i) excellent reproducibility owing to the easy renewal of the electrode surface avoiding any hysteresis effect (i.e., a new identical drop is generated for each measurement to be accomplished); (ii) a wide cathodic potential window originating from the passive hydrogen evolution and solvent electrolysis; (iii) the ability to form amalgams with many redox-active metal ions; and (iv) the achievement of (sub)nanomolar limits of detection. On the other hand, the main controversy of the HMDE usage is the high toxicity level of mercury, which has motivated the scientific community to question whether the HMDE deserves to continue being used despite its unique capability for multi-metal detection. In this work, the simultaneous determination of Zn2+, Cd2+, Pb2+, and Cu2+ using the HMDE is investigated as a model system to evaluate the main features of the technique. The analytical benefits of the HMDE in terms of linear range of response, reproducibility, limit of detection, proximity to ideal redox behavior of metal ions and analysis time are herein demonstrated and compared to other electrodes proposed in the literature as less-toxic alternatives to the HMDE. The results have revealed that the HMDE is largely superior to other reported methods in several aspects and, moreover, it displays excellent accuracy when simultaneously analyzing Zn2+, Cd2+, Pb2+, and Cu2+ in such a complex matrix as digested soils. Yet, more efforts are required towards the definitive replacement of the HMDE in the electroanalysis field, despite the elegant approaches already reported in the literature.


2019 ◽  
Vol 63 (1) ◽  
Author(s):  
Mehdi Jalali ◽  
Zeinab Deris Falahieh ◽  
Mohammad Alimoradi ◽  
Jalal Albadi ◽  
Ali Niazi

The electrochemical behavior of Bi+3 ions on the surface of a glassy carbon electrode, in acidic media and in the presence of tamoxifen, was investigated. Cyclic voltammetry, chronoamperometry, differential pulse voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy with energy-dispersive X-ray spectroscopy were used to find the probable mechanism contributing to the reduction of the peak height of bismuth oxidation with an increase in the concentration of tamoxifen. The obtained results show a slight interaction between the bismuth species and tamoxifen which co-deposit on the surface of glassy carbon electrode. Therefore, the reduction in the peak height of bismuth oxidation as a function of tamoxifen concentration was used to develop a new differential pulse anodic striping voltammetry method for determination of trace amount of tamoxifen. The effects of experimental parameters on the in situ DPASV of Bi+3 ions in the presence of tamoxifen shown the optimal conditions as: 2 mol L-1 H2SO4 (1% v v-1 MeOH), a deposition potential of -0.5 V, a deposition time of 60 s, and a glassy carbon electrode rotation rate of 300 rpm. The calibration curve was plotted in the range of 0.5 to 6 µg mL-1 and the limits of detection and quantitation were calculated to be 3.1 × 10-5 µg mL-1 and 1.0 × 10-4 µg mL-1, respectively. The mean, RSD, and relative bias for 0.5 µg mL-1 (n=5) were found to be 0.49 µg mL-1, 0.3%, and 2%, respectively. Finally, the proposed method was successfully used for the determination of tamoxifen in serum and pharmaceutical samples.


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