title: Separation of homologues and isomers of linear alkylbenzenesulfonates by capillary electrophoresis with sodium dodecyl sulfate, carboxylic acids and bile salts.
abstract: The ability of several anionic compounds, including carboxylic and dicarboxylic acids, sodium dodecyl sulfate (SDS), and sodium deoxycholate (SDC) and other bile salts, to separate the C(10)-C(13) homologues and the corresponding 20 positional isomers of linear alkylbenzenesulfonates (LAS) by capillary electrophoresis was studied. Up to 19 peaks and a shoulder were observed with a background electrolyte (BGE) containing 10 mM phosphate (pH 6.8), 30% acetonitrile and 40 mM SDS, and 18 peaks were obtained with a BGE containing 10 mM borate (pH 9), 40% ethanol and 40 mM palmitic acid (PA). Resolution increased with the alkyl chain length of the carboxylic acid. Dicarboxylic acids with a short alkyl chain, as azelaic acid, were useful to separate the homologues without distinguishing between the isomers. Up to 16 peaks and a shoulder were distinguished with SDC. Resolution decreased with the other bile salts. The 6-C(11)/5-C(11) isomer pair was better resolved with SDC than with SDS, and the 2-C(12) isomer was isolated using both PA and SDC, but not with SDS. Only the 7-C(13)/6-C(13) pair could not be resolved with any of the discriminating agents used.
authors.affiliation: Departament de Química Analítica, Universitat de Barcelona, Barcelona, Spain.
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Herrero-Martínez
authors.forename: Ernesto F
authors.initials: EF
authors.lastname: Simó-Alfonso
authors.forename: Guillermo
authors.initials: G
authors.lastname: Ramis-Ramos
mesh_terms: D001647:Bile Acids and Salts / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000379:methods*; D007536:Isomerism; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D013451:Sulfonic Acids / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D001647:Bile Acids and Salts; D002264:Carboxylic Acids; D013451:Sulfonic Acids; D012967:Sodium Dodecyl Sulfate