Detection of an adsorption step in fast charge-transfer reactions using chronocoulometry and pulse polarography: Application to the reduction of thallium(I)-dicyclohexyl-18-crown-6 complex at the DME
✍ Scribed by L. Pospíšil; J. Kůta; V. utić
- Publisher
- Elsevier Science
- Year
- 1974
- Weight
- 406 KB
- Volume
- 52
- Category
- Article
- ISSN
- 0022-0728
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✦ Synopsis
Potentiostatic techniques using double-step large amplitude perturbation have been developed and succesfully applied for various investigations of adsorption effects coupled with electrode reactions. Chronocoulometric read-out of the electrode response for a constant potential step was worked-out by Anson's group 1 and for the case of continuously variable potential steps a coulometric version of pulse polhrography (p.p.) wa~ developed by Chevalet and Kimmerle 2' 3
Recent results 4 on reactant adsorption obtained from admittance measurements of thallium~ticyclohexyl-18-crown-6 complex reduction revealed a somewhat peculiar overlap of an adsorption potential region with that of faradaic reduction. In such a case adsorbed reactant may be looked upon more as an intermediate species rather than as a stable adsorbate. Chronocoulometric investigations so far published have dealt with systems showing pronounced adsorption, outside the potential region of a faradaic process. An independent adsorption detection in the system mentioned above by means of chronocoulometry and pulse polarography is the subject of this paper. Some observations concerning the detection limit of the three methods used will be made.
EXPERIMENTAL
Apparatus and procedure