A novel fused-silica capillary dropping mercury electrode with long drop-time and its application on determination of critical micelle concentration.
Talanta
; 84(1): 187-91, 2011 Mar 15.
Article
em En
| MEDLINE
| ID: mdl-21315918
ABSTRACT
A novel long drop time mercury electrode has been constructed from common fused-silica capillary (50 µm I.D., 360 µm E.D.). Proposed device provides reproducible mercury drops with typical lifetime 40-120 s. The electrode was used for a set of electrocapillary measurements aimed at determination of critical micelle concentration of anionic surfactants by a convection controlled drop-time technique. A critical micelle concentration of sodium dodecyl sulfate 5.6 ± 0.4 mmol L(-1) and 4.3 ± 0.4 mmol L(-1) were obtained in 1 mmol L(-1) and 5 mmol L(-1) phosphate buffer (pH 7.0), respectively. The values were comparable to those obtained from conductometric measurements under the same conditions (7.0 ± 0.1 mmol L(-1) and 5.2 ± 0.1 mmol L(-1), respectively) and the difference was explained in accordance with theory of hemi-micelle formation.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Dióxido de Silício
/
Eletroumectação
/
Mercúrio
/
Micelas
Idioma:
En
Ano de publicação:
2011
Tipo de documento:
Article