Analysis of trace nickel by square wave stripping voltammetry using chloropalladium(II) complex-modified MWCNTs paste electrode

2017 ◽  
Vol 240 ◽  
pp. 848-856 ◽  
Author(s):  
Mohamad Idris Saidin ◽  
Illyas Md Isa ◽  
Mustaffa Ahmad ◽  
Norhayati Hashim ◽  
Sulaiman Ab Ghani
Keyword(s):  
Stripping Voltammetry ◽  
Square Wave ◽  
Square Wave Stripping Voltammetry ◽  
Paste Electrode

Voltammetric study of 2-guanidinobenzimidazole: Electrode mechanism and determination at mercury electrode

2011 ◽  
Vol 76 (12) ◽  
pp. 1699-1715 ◽  
Author(s):  
Sławomira Skrzypek ◽  
Valentin Mirceski ◽  
Sylwia Smarzewska ◽  
Dariusz Guziejewski ◽  
Witold Ciesielski
Keyword(s):  
Time Window ◽  
Mercury Electrode ◽  
Linear Sweep Voltammetry ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Protonated Form ◽  
Citrate Buffer ◽  
Square Wave ◽  
Biological Interest ◽  
Square Wave Stripping Voltammetry

Although 2-guanidinobenzimidazole (GBI; CAS: 5418-95-1) is a compound of biological interest, generally there is a lack of electrochemical studies and the methods of its determination. The GBI behavior at a mercury electrode was analyzed under conditions of linear sweep voltammetry (LSV), differential pulse voltammetry (DPV), square-wave voltammetry (SWV) and square-wave stripping voltammetry (SWSV). Although GBI is electrochemically inactive at mercury electrode it adsorbs at the mercury surface and catalyzes effectively the hydrogen evolution reaction. Theoretical analysis of two possible pathways, according to which the GBI electrode mechanism can be explained, is performed. Simple analysis of peak current and potential with respect to available time window, i.e. change of frequency can be helpful in discerning the character of the recorded SW current. The established electrode mechanism is assumed to involve a preceding chemical reaction in which the adsorbed catalyst (GBIads) is protonated and the protonated form of the catalyst (GBIH+(ads)) is irreversibly reduced at potential about –1.18 V vs Ag|AgCl (citrate buffer pH 2.5). New methods of voltammetric determination of 2-guanidinobenzimidazole were developed. The detection and quantifications limits were found to be 1 × 10–7, 1 × 10–6 mol l–1 (SWV); 8 × 10–8, 9 × 10–7 mol l–1 (SWSV); 4 × 10–7, 2 × 10–6 mol l–1 (DPV) and 6 × 10–7, 3 × 10–6 mol l–1 (LSV), respectively.

Voltammetric behavior and quantification of the anti-leukemia drug imatinib in bulk form, pharmaceutical formulation, and human serum at a mercury electrode

2004 ◽  
Vol 82 (7) ◽  
pp. 1203-1209 ◽  
Author(s):  
E Hammam ◽  
H S El-Desoky ◽  
A Tawfik ◽  
M M Ghoneim
Keyword(s):  
Cyclic Voltammetry ◽  
Human Serum ◽  
Electrochemical Behavior ◽  
Stripping Voltammetry ◽  
Pharmaceutical Formulation ◽  
Myelogenous Leukemia ◽  
Hanging Mercury Drop Electrode ◽  
Square Wave ◽  
Mercury Drop Electrode ◽  
Square Wave Stripping Voltammetry

Imatinib (GleevecTM, ST1571) exemplifies the successful development of a rationally designed molecularly targeted therapy for treatment of a specific cancer. It is a highly promising new drug for the treatment of chronic myelogenous leukemia in blast crisis, in the accelerated or chronic phase after interferon failure or intolerance. The electrochemical behavior of imatinib was studied in Britton–Robinson (B–R) buffers of pH 2 to 11 by means of cyclic voltammetry at a hanging mercury drop electrode. The voltammograms showed a single 2-electron irreversible cathodic peak, which may be attributed to reduction of the C=O double bond of the imatinib molecule. Imatinib exhibited a strong adsorption onto the electrode surface especially in B–R buffers of pH 6 and 7. The adsorptive response of the drug was optimized with respect to the pH of the electrolysis medium, accumulation variables, and instrumental parameters using a square-wave stripping voltammetry technique. A fully validated, simple, sensitive, precise, and selective square-wave adsorptive cathodic stripping voltammetric procedure is described for trace determination of imatinib. The limits of detection (LOD) and quantitation (LOQ) of the bulk imatinib, following preconcentration for 150 s onto the hanging mercury drop electrode, were found to be 2.6 × 10–10 and 8.7 × 10–10 mol/L, respectively. The proposed procedure was successfully applied for quantitation of imatinib in pharmaceutical formulation (Glivec®) and spiked human serum, without the necessity for sample pretreatment or time-consuming extraction or evaporation steps prior to analysis of the drug. LOD and LOQ of 4.6 × 10–10 and 1.5 × 10–9 mol/L, respectively, were achieved after 120 s of preconcentration of the drug spiked in human serum.Key words: imatinib, GleevecTM, Glivec®, ST1571, cyclic voltammetry, square-wave stripping voltammetry, electrochemical behavior, quantification, pharmaceutical formulation, human serum.

Administering Pesticide Assays in In Vivo-Implanted Biosensors

2008 ◽  
Vol 61 (10) ◽  
pp. 826 ◽  
Author(s):  
Suw Young Ly ◽  
Young Sam Jung ◽  
Chang Hyun Lee ◽  
Bang Won Lee
Keyword(s):  
Carbon Nanotube ◽  
Stripping Voltammetry ◽  
Brain Cell ◽  
Relative Standard ◽  
Square Wave Stripping Voltammetry ◽  
Fruit Samples ◽  
Carbon Nanotube Paste Electrode ◽  
Analytical Time ◽  
Paste Electrode

An analytical pesticide assay of O-ethyl-O-4-(nitrophenyl)phenyl phosphonothioate (EPN) was carried out using the following: a carbon nanotube paste electrode, a mercury-immobilized carbon nanotube paste electrode, a glassy carbon electrode, a metal–gold electrode, and a DNA-immobilized carbon nanotube paste electrode (DPE), which is two-fold more sensitive than other sensors. The DPE was optimized using cyclic and square wave stripping voltammetry. Linear working ranges approached 5–55 mg L–1 EPN and the nano-range of 10–210 ng L–1 in a 0.1 mol L–1 NH4H2PO4 electrolyte solution, with a speedy analytical time of 30-s stripping. The detection limit was 2.57 ng L–1 (7.94 × 10–12 mol L–1), and the precision was 0.102% relative standard deviation (n = 15) at the 10.0 mg L–1 EPN spike. This indicates that the method is more sensitive than common voltammetric methods. This method was applied to fruit samples using patch- and needle-type electrodes, specifically on the skin tissues of an orange and an apple. Moreover, the implanted electrode was interfaced with a fish brain cell at the electrochemical workstation. Results showed that the aforementioned method can be used to conduct a pesticide assay in neuro-treated and non-treated cell systems.

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