scholarly journals Development of Gold Electrode Modified With Sodium Diethyldithiocarbamate-Nafion to Determine Selenium (IV) in Bulk and in Dosage Formulations Using Differential Pulse Anodic Stripping Voltammetric Analysis

Author(s):  
Abdul Aziz Ramadan ◽  
◽  
Hasna Mandil ◽  
Abdul Rahman Shikh-Debes ◽  
◽  
...  
2018 ◽  
Vol 15 (2) ◽  
pp. 6248-6261 ◽  
Author(s):  
Abdul Aziz Ramadan ◽  
Hasna Mandil ◽  
Abdulrahman Shikh-Debes

The effect of gold electrode modified with 2,3-Diaminonaphthalene (GEMDANN) or multi-modified or a mixture 2,3-diaminonaphthalene and o-phenylenediamine -nafion (GEMDAN-OPDAN) on determination of selenium (IV) using differential pulse anodic stripping voltammetric analysis (DPASVA) has been studied. Various parameters (electrolyte, deposition time, pulse duration, pulse amplitude, etc.) are affecting determination of the Se(IV) in HClO4 (0.2 M) at pH 0.22 were examined. Under the optimum conditions, liner calibration graph, Ip=f(CSe4+), were obtained in the concentration ranges of 5x10-8 - 1x10-6 M (3.948 -78.96 ng.mL-1 ) with relative standard deviations (RSD) 4.2% and detection limit 0.056 ng.mL-1, and 1x10-9 -1x10-6 M (0.07896 -78.96 ng.mL-1 ) with relative standard deviations (RSD) 4.9% and detection limit was 0.014 ng.mL-1 on GEMDANN and GEMDAN-OPDAN, respectively. This method showed a good accumulation efficiency for selenium and good resistance to interferences from metal ions as well as those associated with selenium in pharmaceuticals. The results for the determination of Se4+ using GEMDAN-OPDAN (multi-modified) were more sensitive (about 50 times) than that obtained using GEMDANN.


Author(s):  
Abdul Azizs Ramadan ◽  
Hasna Mandil ◽  
Abdulrahman Shikh-debes

Objective: A simple, direct and very sensitive differential pulse anodic stripping voltammetric analysis (DPASVA) of selenium (IV) in bulk and in dosage formulations using a gold electrode multi-modified with a mixture of 3,3′-diaminobenzidine.4HCl (Dab) and vitamin E (VE)-Nafion (AuEMDabVEN) has been studied.Methods: The method involves the study of various parameters (electrolyte, deposition time, pulse duration, pulse amplitude, etc.) affecting the Se(IV) determination. The proposed method was validated for specificity, linearity, precision and accuracy, repeatability, sensitivity (LOD and LOQ), robustness and solution stability with an average recovery of 98.1-100.32%.Results: Se(IV)was determined in an aqueous HClO4 (0.2M) medium of pH 0.22 at an accumulation potential of-250 mV and an accumulation time of 200 s for CSe(IV) at 1x10-8 to 1x10-6 mol/l (0.7896-78.96 ng/ml) and 350 s for CSe(IV) at 1x10-9 to 1x10-8 mol/l (0.07896-0.7896 ng/ml) with relative standard deviations (RSD)2.4% and 4.8%, respectively.Conclusion: This method showed very sensitive results for the determination of Se(IV) using an AuEMDabVEN than that obtained using the individual Dab or VE. This method could be applicable for the quantitative determination of the bulk Se(IV) as well as dosage formulations.


Environments ◽  
2018 ◽  
Vol 5 (11) ◽  
pp. 120 ◽  
Author(s):  
Charlton van der Horst ◽  
Bongiwe Silwana ◽  
Emmanuel Iwuoha ◽  
Vernon Somerset

The emission of toxic compounds by increasing anthropogenic activities affects human health and the environment. Heavy road traffic and mining activities are the major anthropogenic activities contributing to the presence of metals in the environment. The release of palladium (Pd), platinum (Pt), and rhodium (Rh) into the environment increases the levels of contamination in soils, road sediments, airborne particles, and plants. These Pd, Pt, and Rh in road dusts can be soluble and enter aquatic environment posing a risk to environment and human health. The aim of this study is to determine the levels of Pd, Pt, and Rh with spectroscopy and voltammetric methods. Potential interferences by other metal ions (Na(I), Fe(III), Ni(II), Co(II)) in voltammetric methods have also been investigated in this study. At all the sampling sites very low concentrations of Pd, Pt, and Rh were found at levels that range from 0.48 ± 0.05 to 5.44 ± 0.11 ng/g (dry weight (d.wt)) for Pd(II), with 17.28 ± 3.12 to 81.44 ± 3.07 pg/g (d.wt) for Pt(II), and 14.34 ± 3.08 to 53.35 ± 4.07 pg/g (d.wt) for Rh(III). The instrumental limit of detection for Pd, Pt, and Rh for Inductively Coupled Plasma Quadrupole-based Mass Spectrometry (ICP-QMS) analysis was found to be 3 × 10−6 µg/g, 3 × 10−6 µg/g and 1 × 10−6 µg/g, respectively. In the case of voltammetric analysis the instrumental limit of detection for Pd(II), Pt(II), and Rh(III) for differential pulse adsorptive stripping voltammetry was found to be 7 × 10−8 µg/g, 6 × 10−8 µg/g, and 2 × 10−7 µg/g, respectively. For the sensor application, good precision was obtained due to consistently reproduced the measurements with a reproducibility of 6.31% for Pt(II), 7.58% for Pd(II), and 5.37% for Rh(III) (n = 10). The reproducibility for ICP-QMS analysis were 1.58% for Pd(II), 1.12% for Pt(II), and 1.37% for Rh(III) (n = 5). In the case of repeatability for differential pulse adsorptive stripping voltammetry (DPAdSV) and ICP-QMS, good standard deviations of 0.01 for Pd(II); 0.02 for Pt(II), 0.009 for Rh(III) and 0.011 for Pd, 0.019 for Pt and 0.013 for Rh, respectively.


Sign in / Sign up

Export Citation Format

Share Document