Dynamically formed admicelle layer to control the amplitude of cathodic electroosmotic flow

• Tipo: Artigo em Revista Científica Internacional
• Data: 2012

Autores

Guillaume Erny (Autor) Outra; Goncalves, BM (Autor) Outra; Esteves, VI (Autor) Outra

Revista

Título: Journal of Chromatography A

Vol. 1256

Páginas: 271-275

ISSN: 0021-9673

Editora: Elsevier

Indexação

ISI Web of Knowledge - 4 Citações

Scopus - 7 Citações

Outras Informações

ID Authenticus: P-002-5DJ

DOI: 10.1016/j.chroma.2012.07.076

Abstract (EN): In this manuscript, a method to precisely adjust the amplitude of a cathodic electroosmotic flow is described. The method uses a capillary pre-coated with a cationic polymer (polybrene), in presence of an anionic surfactant such as sodium dodecyl sulfate. At low concentration of surfactant, molecules will self-assemble to form an immobilized hemimicelle layer with the anionic "head" in contact with the cationic coating and the hydrophobic tail reaching into the background electrolyte. At higher concentration, surfactant molecules in solution will then interact, via hydrophobic interactions, to form an admicelle layer. It has been demonstrated that the admicelle layer can be constructed with either pure anionic surfactant (SOS), or a mixture of anionic and neutral surfactants. Admicelle coatings can be used to control the electroosmotic flow (EOF). While at low surfactant concentration the amplitude of the EOF depends on the concentration of the surfactants concentration, when this concentration reaches the critical admicelle concentration the EOF becomes near constant. The amplitude of the EOF can also be adjusted via the relative proportion of neutral and ionic surfactant in solution. Using this approach, the EOF was varied from 0.450 to 3.848 x 10(-8) m(2) V-1 s(-1) with a precision below 0.050 x 10(-8) m(2) V-1 s(-1) (standard deviation measured with three replicates). The coating has been tested using a mix of triazines (atrazine, simazine and terbuthylazine) and a beer sample. With the beer sample an average relative standard deviation of 1.5% for the migration time and of 2.2% for the corrected peak area was obtained.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 5