Differential pulse voltammetric determination of propylthiouracil and methylthiouracil using their catalytic effects on the electrochemical oxidation of catechol

Shahrokhian, S ; Sharif University of Technology | 2007

159 Viewed
  1. Type of Document: Article
  2. Publisher: 2007
  3. Abstract:
  4. The electrochemical behavior of catechol in the presence of propylthiouracil (PTU) and methylthiouracil (MTU) at a glassy carbon electrode is thoroughly investigated. The cyclic voltammetric studies of the systems are performed in different pHs and sweep rates. The results of the voltammetric foundations show an electrocatalytic oxidation of catechol in the presence of PTU and MTU, leading to a remarkable increase in the anodic peak current of catechol together with the contemporaneous disappearance of the corresponding cathodic wave. The presented mechanism shows the nucleophilic addition/reduction of the electro-generated o-quinone by the PTU or MTU, which produced chemically reduced adducts whose subsequent re-oxidation at the electrode surface leads to a considerable amplification of the anodic peak current. The increasing of the anodic peak current shows a linear correlation with the concentration of PTU and MTU. The spectrophotometric investigations are used to confirm the interaction of considering thiols with the electrochemically produced o-quinone during the controlled-potential coulometry. The effect of various biological thiols, such as cysteine, penicillamine, N-acetyl cysteine, glutathione and captopril on the electrochemical behavior of catechol is investigated in the same conditions. The results represent the unique electrocatalytic effect of PTU and MTU for improving the anodic peak current of catechol and exhibit a very sensitive and relatively selective method for the voltammetric detection of the pointed thiols. A linear range from 0.1 to 10.0 μM with a detection limit of 0.05 μM is obtained for the determination of PTU. The linear range for MTU, using differential pulse voltammetry, was from 0.1 to 5.0 μM with a detection limit of 0.07 μM. The proposed method showed to be useful for the sensitive detection of PTU and MTU among pharmaceutical and biological thiols. © 2007 by ESG
  5. Keywords:
  6. Catechol ; Propylthiouracil ; Cyclic voltammetry ; Differential pulse voltammetry ; Methylthiouracil ; Electrocatalysis
  7. Source: International Journal of Electrochemical Science ; Volume 2, Issue 2 , 2007 , Pages 158-168 ; 14523981 (ISSN)
  8. URL: https://www.academia.edu/18808714/Differential_pulse_voltammetric_determination_of_propylthiouracil_and_methylthiouracil_using_their_catalytic_effects_on_the_electrochemical_oxidation_of_catechol