Anodic oxidation of mercury in the presence of thioether acids: Methane-1,1-bis-mercaptoacetic acid

1987 ◽  
Vol 52 (3) ◽  
pp. 616-625 ◽  
Author(s):  
E. Casassas ◽  
M. Esteban ◽  
C. Ariño
Keyword(s):  
Cyclic Voltammetry ◽  
Anodic Oxidation ◽  
Stripping Voltammetry ◽  
Electrode Process ◽  
Mercaptoacetic Acid ◽  
Anodic Process ◽  
Hanging Mercury Drop Electrode ◽  
No Adsorption ◽  
Cathodic Stripping Voltammetry ◽  
Mercury Drop Electrode

The anodic oxidation of mercury in the presence of methane-1,1-bis-mercaptoacetic acid (MBMA) has been studied by DCr, DP, AC1, and AC2 polarography, cyclic voltammetry, and coulometry. The electrode process is controlled by the adsorption of the product formed according to: Hg + 2 H(2-n)Ln- → H(2-n)HgL2n- + (2-n) H+ + 2e with n = 0 at pH < pK1, n = 1 at pK1 < pH < pK2, and n = 2 at pH > pK2. No adsorption of MBMA is observed. The behaviour of MBMA at a hanging mercury drop electrode (HMDE) by cathodic stripping voltammetry (CSV) has been also studied. At MBMA concentrations above 1 10-6 mol l-1, the stripping voltammograms showed two well defined peaks, at c. -0.140 V and at c. -0.300 V. The anodic process occurring during the pre-electrolysis in CSV is described by the formation of a Hg(I) compound: 2 Hg + 2 H(2-n)Ln- → H(2-n)Hg2L2(2-2n)+ + 2e followed by its disproportionation: H(2-n)Hg2L2(2-2n)+ →c H(2-n)HgL2(2-2n)+ + Hg,where n has the above-mentioned values.

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.

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