geoscience.net logo
+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Laser-activated voltammetry: measurement of the diffusion coefficients of electropassivating species. Application to pyrrole and phenol in aqueous solution


, : Laser-activated voltammetry: measurement of the diffusion coefficients of electropassivating species. Application to pyrrole and phenol in aqueous solution. Analytical Chemistry 72(8): 1830-1834

Clean electrode surfaces can be achieved during the electrolysis of otherwise passivating species in aqueous and other solutions by means of surface ablation using a 10-Hz pulsed Nd:YAG 532-nm laser. This ability to remove passivating electrolytically generated layers on glassy carbon and platinum electrodes is shown first by an investigation of the stripping peaks formed from the electrogeneration of the neutral forms of methyl viologen and heptyl viologen during reduction in aqueous solution of dications. Next, laser ablation was conducted under well-defined hydrodynamic conditions using a channel flow cell to identify laser power thresholds below which transport-limited currents could be seen, which were in quantitative agreement with those expected in the absence of irradiation. Levich plots recorded in the channel flow cell for K4Fe(CN)6 at glassy carbon and platinum electrodes showed such agreement for laser intensities lower than 0.17 and 0.65 W cm(-2), respectively. Working at intensities below these thresholds, steady-state voltammetry was observed for the oxidation of both phenol and pyrrole at glassy carbon and platinum electrodes, respectively, in aqueous solution. The diffusion coefficients of these two species were then measured under hydrodynamic conditions using laser ablation voltammetry to continuously clean the surface. Diffusion coefficients were inferred using the Levich equation. The result for phenol at a pH of 12 in aqueous solution was 0.9 (+/-0.1) x 10(-5) cm2 s(-1), which is in good agreement with an independent nonelectrochemical method. The diffusion coefficient of pyrrole in aqueous solution was similarly evaluated as 1.25 (+/-0.1) x 10(-5) cm2 s(-1).

US$29.90

PMID: 10784150


Other references

Stephens, T.W., 1986: After the famine. Food aid policy and management issues in sub-Saharan Africa. The large amount of food aid that was required to meet Africa's emergency food situation resulted in the postponement of some fundamental decisions that were being taken about food aid use in sub-Saharan Africa. Now the donor community and re...

Lu, Q., 2005: Seamless cloning and gene fusion. Gene fusion technology is a key tool in facilitating gene function studies. Hybrid molecules in which all the components are joined precisely, without the presence of intervening and unwanted extraneous sequences, enable accurate studies of molecu...

Bijl, R.V.; Ketting, E., 1991: Future scenario's Dementia 1990-2010--various major points from the scenario report 'Care for mental health in the future'. This paper describes major points of a study on the future of dementia in the period 1990-2010. By means of a literature review and consultation of experts in a Delphi-study exploratory scenarios and a target-setting scenario were constructed. The...

Conn, P.J.; Sanders-Bush, E., 1984: Selective 5HT-2 antagonists inhibit serotonin stimulated phosphatidylinositol metabolism in cerebral cortex. Evidence suggests that the serotonin 5HT-1 receptor site is functionally linked to adenylate cyclase in the brain, but a biochemical effector system which is linked to the serotonin 5HT-2 receptor site has not been found. In the present paper we r...

Court, J.H.; Cameron, I.A., 1963: Psychomotor Assessment Of The Effects Of Haloperidol. Perceptual and Motor Skills 17: 168-170

Grossman, Richard A., 1995: Women cannot discriminate between paracervical block techniques applied to opposite sides of the cervix. The purpose of this study was to determine whether women can discriminate better from less effective paracervical block techniques applied to opposite sides of the cervix. If this discrimination could be made, it would be possible to compare diffe...

Young, M.W., 1947: Anatomical factors in senile alopecia; experimental production of baldness. Anatomical Record 97(3): 378-378

Hinman, H.; Erickson, D.; Willett, G., 1982: 1982 crop enterprise budgets for the Palouse region of Washington and Idaho. Extension bulletin Washington State University Cooperative Extension Service: 82 (1030)

Darlington, P.J. jr., 1953: West Indian Carabidae (Coleoptera). The Bahama species. American Museum Novitates New York No. 1650; 1-16

Kustova, Y.; Sei, Y.; Basile, A.S., 2000: Elevated glutamate levels contribute to increased blood-brain barrier permeability in LP-BM5 infected mice. Journal of Neurovirology 6(Supplement 1): S107, May