Water in soybean oil microemulsions as medium for electrochemical measurements

Microemulsions of water in soybean oil (w/o ME) were prepared with sodium dodecyl sulfate (SDS) as surfactant and amyl or isoamyl alcohol, as co-surfactants. Microemulsions containing 40.0% oil, 43.2% alcohol, 10.8% SDS and 6.0% water in weight, in the ratio 1:4 [SDS]:[alcohol] showed the highest th...

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Bibliographic Details
Published in:Journal of the Brazilian Chemical Society 2003-08, Vol.14 (4), p.628-636
Main Authors: Mendonça, Carla R. B., Bica, Clara I. D., Piatnicki, Clarisse M. S.
Format: Article
Language:English
Subjects:
CHEMISTRY, MULTIDISCIPLINARY
ferrocene
microemulsions
oleic acid
soybean oil
voltammetry
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Summary:Microemulsions of water in soybean oil (w/o ME) were prepared with sodium dodecyl sulfate (SDS) as surfactant and amyl or isoamyl alcohol, as co-surfactants. Microemulsions containing 40.0% oil, 43.2% alcohol, 10.8% SDS and 6.0% water in weight, in the ratio 1:4 [SDS]:[alcohol] showed the highest thermodynamic stability. The aqueous droplet size and its diffusion coefficient Dw/o in the ME were determined through dynamic light scattering (DLS). Voltammetric measurements in the ME at a Pt disk ultramicroelectrode (ume) evidenced the oxidation of both water and ferrocene (Fc), and the reduction of oleic acid. The Dw/o values calculated from the limiting current being lower than the ones obtained from DLS indicate that water oxidation probably requires diffusion towards the electrode of both the droplets and the water molecules from inside the droplets. The results show that electroanalytical determinations can be carried out in w/o ME.
ISSN:0103-5053
1678-4790
DOI:10.1590/S0103-50532003000400021