Voltammetric Determination of Fluoren-9-ol and 2-Acetamidofluorene Using Carbon Paste Electrodes

2005 ◽  
Vol 70 (3) ◽  
pp. 292-304 ◽  
Author(s):  
Natalija German ◽  
Saulius Armalis ◽  
Jiří Zima ◽  
Jiří Barek

Square wave voltammetry and differential pulse voltammetry have been used for the determination of 2-acetamidofluorene and fluoren-9-ol using carbon paste electrodes, following the study of the influence of the carbon paste composition on the voltammetric signals of the analytes. The methods are based on the oxidation of the above compounds and they include adsorptive accumulation of the analyte on the surface of the working electrode. The limit of detection was 1 μmol l-1for fluoren-9-ol in a medium of 0.1 M H2SO4, and 40 nmol l-1for 2-acetamidofluorene in Britton-Robinson buffer (pH 7).

2011 ◽  
Vol 76 (5) ◽  
pp. 383-397 ◽  
Author(s):  
Ferenc T. Pastor ◽  
Hana Dejmková ◽  
Jiří Zima ◽  
Jiří Barek

The possibility of determination of chloramphenicol by differential pulse voltammetry at four different carbon paste electrodes, in the full pH range (2–12) of Britton–Robinson (BR) buffer was investigated. Electrodes were prepared by mixing spectroscopic graphite powder or glassy carbon microbeads with mineral oil (Nujol) or tricresyl phosphate. Under optimal conditions (BR buffer pH 12, the electrode prepared from glassy carbon microbeads and tricresyl phosphate), linear calibration graph was obtained only in 10–5 M chloramphenicol concentration range. Determination of lower concentrations of chloramphenicol was complicated by irreproducible peak of oxygen from the carbon paste which overlapped with peak of chloramphenicol. Addition of sodium sulfite removed the oxygen peak without influence on the peak of chloramphenicol. Under optimal conditions (electrode paste made from glassy carbon microbeads, BR buffer pH 10 and 0.5 M sodium sulfite), straight calibration line was obtained in the 10–6 and 10–5 M chloramphenicol concentration range. Limit of determination was 5 × 10–7 mol/l.


2015 ◽  
Vol 7 (8) ◽  
pp. 3411-3418 ◽  
Author(s):  
Gustavo Stoppa Garbellini ◽  
Romeu C. Rocha-Filho ◽  
Orlando Fatibello-Filho

A cathodically pretreated boron-doped diamond electrode is successfully used to determine ciprofloxacin (CIP) by differential pulse voltammetry and to infer the type of binding of CIP to DNA by square-wave voltammetry.


The techniques of normal and differential pulse voltammetry are presented together with equations describing these techniques. A number of specific applications for both differential and normal pulse, including determination of As III in sewage and the determination of sulphide, are presented. Advantages of amperometric titrations in eliminating ‘background’ errors are shown, with the titration of Cu II with EDTA as a specific example. The use of square-wave voltammetry, a new, rapid-pulse technique, is presented, and an application in which this technique is employed in an electrochemical high performance chromatographic detector used for nitrosamine analysis is discussed.


2004 ◽  
Vol 69 (8) ◽  
pp. 1590-1599 ◽  
Author(s):  
Xiaobo Ji ◽  
Shengshui hu

A carbon paste electrode modified with montmorillonite for the determination of Eu(III) was developed. This chemically modified electrode exhibits strong and stable electroactivity for Eu(III). Square wave voltammetry (SWV) of Eu(III) was evaluated with respect to the quantity of modifier, pH of electrolyte solution, accumulation potential and time. The stripping peak currents increase linearly with concentrations of Eu(III) from 1.0 × 10-7 to 2.0 × 10-5 mol l-1. The detection limit is estimated to be 4 × 10-8 mol l-1 (S/N = 3). The recommended method has been applied to the quantitation of Eu(III) in stream sediment samples; the results obtained by the SWV approach are in good agreement with reference values.


Author(s):  
P. H. B. Oliva ◽  
J. M. T. Katayama ◽  
E. N. Oiye ◽  
B. Ferreira ◽  
M. F. Ribeiro ◽  
...  

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 714
Author(s):  
Gaber A. M. Mersal ◽  
Hamdy S. El-Sheshtawy ◽  
Mohammed A. Amin ◽  
Nasser Y. Mostafa ◽  
Amine Mezni ◽  
...  

The agricultural use of organophosphorus pesticides is a widespread practice with significant advantages in crop health and product yield. An undesirable consequence is the contamination of soil and groundwater by these neurotoxins resulting from over application and run-off. Here, we design and synthesize the mononuclear zinc(II) complexes, namely, [Zn(AMB)2Cl](ClO4) 1 and [Zn(AMB)2(OH)](ClO4) 2 (AMB = 2-aminomethylbenzimidazole), as artificial catalysts inspired by phosphotriesterase (PTE) for the hydrolysis of organophosphorus compounds (OPs) and simultaneously detect the organophosphate pesticides such as fenitrothion and parathion. Spectral and DFT (B3LYP/Lanl2DZ) calculations revealed that complexes 1 and 2 have a square-pyramidal environment around zinc(II) centers with coordination chromophores of ZnN4Cl and ZnN4O, respectively. Both 1 and 2 were used as a modifier in the construction of a biomimetic sensor for the determination of toxic OPs, fenitrothion and parathion, in phosphate buffer by square wave voltammetry. The hydrolysis of OPs using 1 or 2 generates p-nitrophenol, which is subsequently oxidized at the surface of the modified carbon past electrode. The catalytic activity of 2 was higher than 1, which is attributed to the higher electronegativity of the former. The oxidation peak potentials of p-nitrophenol were obtained at +0.97 V (vs. Ag/AgCl) using cyclic voltammetry (CV) and +0.88 V (vs. Ag/AgCl) using square wave voltammetry. Several parameters were investigated to evaluate the performance of the biomimetic sensor obtained after the incorporation of zinc(II) complex 1 and 2 on a carbon paste electrode (CPE). The calibration curve showed a linear response ranging between 1.0 μM (0.29 ppm) and 5.5 μM (1.6 ppm) for fenitrothion and 1.0 μM (0.28 ppm) and 0.1 μM (0.028 ppm) for parathion with a limit of detection (LOD) of 0.08 μM (0.022 ppm) and 0.51 μM (0.149 ppm) for fenitrothion and parathion, respectively. The obtained results clearly demonstrated that the CPE modified by 1 and 2 has a remarkable electrocatalytic activity towards the hydrolysis of OPs under optimal conditions.


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