Cathodic Stripping Voltammetry of 2-Thiouracils

2005 ◽  
Vol 70 (2) ◽  
pp. 188-197 ◽  
Author(s):  
Michał Kasprzak ◽  
Witold Ciesielski ◽  
Sławomira Skrzypek
Keyword(s):  
Analytical Method ◽  
Mercury Electrode ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Antithyroid Drugs ◽  
Chemical Reagents ◽  
Cathodic Stripping Voltammetry ◽  
Electrode Reactions ◽  
Adsorption Processes ◽  
Cathodic Stripping

Four 6-R-2-thiouracils (R = H, methyl, propyl, benzyl) were examined by differential pulse cathodic stripping voltammetry on mercury electrode. The research led to a very sensitive analytical method that allows their determination on nanomolar level. The detection limit of the 6-propyl derivative is as low as 1.0 × 10-9 mol dm-3. The procedure is very simple and utilizes only most common chemical reagents (such as acetate buffer). The buffer concentration plays an important role in the preconcentration stage, due to the adsorption processes accompanying electrode reactions. The new analytical method was tested with commercial samples of various antithyroid drugs.

Electrochemical determination of muscle relaxant drug tetrazepam in bulk form, pharmaceutical formulation, and human serum

2008 ◽  
Vol 62 (2) ◽  
Author(s):  
Mohammed Ghoneim ◽  
Hanaa El-Desoky ◽  
Mohammed El-Ries ◽  
Ashraf Abd-Elaziz
Keyword(s):  
Human Serum ◽  
Mercury Electrode ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Electrochemical Determination ◽  
Differential Pulse Polarography ◽  
Linear Sweep ◽  
Square Wave ◽  
Cathodic Stripping Voltammetry ◽  
Cathodic Stripping

AbstractTetrazepam dissolved in the Britton-Robinson universal buffer of various pH values (2.5–11.5) containing 10 vol. % of ethanol was reduced at the mercury electrode in a single 2-electron irreversible step due to reduction of the 4,5 C=N double bond of the seven-membered ring. Differential pulse polarography (DPP) and adsorptive cathodic stripping voltammetry (AdCSV) techniques (Linear sweep LS, differential pulse DP and square-wave SW modes) for quantification of tetrazepam in bulk form and in myolastan tablets are presented. Moreover, the described linear sweep, differential pulse, and square-wave adsorptive cathodic stripping voltammetry was successfully applied in quantification of tetrazepam in spiked human serum without any prior extraction of the drug. The obtained results showed an increased sensitivity of the described electro-analytical procedures for the quantification of tetrazepam in the following order DPP, DP-AdCSV, LS-AdCSV, and SW-AdCSV, since the observed limits of tetrazepam quantitation by these electroanalytical techniques were 5 × 10−6 mol L−1, 3 × 10−7 mol L−1, 1 × 10−8 mol L−1, and 3 × 10−9 mol L−1, respectively.

Reaction of nucleic acid bases with the mercury electrode: determination of submicromolar concentrations of pyrimidine bases by means of cathodic stripping voltammetry

1980 ◽  
Vol 45 (12) ◽  
pp. 3472-3481 ◽  
Author(s):  
Emil Paleček ◽  
František Jelen
Keyword(s):  
Mercury Electrode ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Deposition Potential ◽  
Pyrimidine Derivatives ◽  
Cathodic Stripping Voltammetry ◽  
Order Of Magnitude ◽  
Pyrimidine Bases ◽  
Cathodic Stripping

Pyrimidine bases commonly occurring in nucleic acids i.e. cytosine, uracil and thymine and further pyrimidine derivatives such as 5-methylcytosine, 5-hydroxymethylcytosine, isocytosine, uracil-6-carboxylic acid (orotic acid), 5-amino-2,4-dioxypyrimidine, 2-amino-4,6-dioxypyrimidine and 4-amino-2,6-dioxypyrimidine and thio derivatives and halogen derivatives of uracil and cytosine were analyzed by means of cathodic stripping voltammetry (CSV). As compared with most of the sulphur-containing substances the deposition potential optima of the pyrimidine derivatives (not containing sulphur) were substantially narrower and shifted to more positive potentials. Cytosine, thymine and uracil can be determined by means of differential pulse CSV at concentrations of the order of magnitude 10-7 - 10-8 mol/l. Nucleosides and nucleotides derived from the pyrimidine bases are inactive and do not substantially interfere with the determination of bases. Bases can be determined even in an excess of DNA and proteins.

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