title: A novel fused-silica capillary dropping mercury electrode with long drop-time and its application on determination of critical micelle concentration.
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.
authors.affiliation: Department of Analytical Chemistry, Faculty of Science, Palacký University, 17 Listopadu 1192/12, 77146 Olomouc, Czech Republic. jitka.souckova@centrum.cz
authors.forename: Jitka
authors.initials: J
authors.lastname: Součková
authors.forename: Jana
authors.initials: J
authors.lastname: Skopalová
authors.forename: Lukáš
authors.initials: L
authors.lastname: Muller
authors.forename: Michaela
authors.initials: M
authors.lastname: Vymětalíková
authors.forename: Petr
authors.initials: P
authors.lastname: Barták
mesh_terms: D003217:Conductometry; D004566:Electrodes; D004573:Electrolytes / Q000737:chemistry; D058874:Electrowetting / Q000379:methods*; D008628:Mercury / Q000737:chemistry*; D008823:Micelles; D012822:Silicon Dioxide / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry; D013997:Time Factors
chemical_list: D004573:Electrolytes; D008823:Micelles; D013501:Surface-Active Agents; D012967:Sodium Dodecyl Sulfate; D012822:Silicon Dioxide; D008628:Mercury