title: Capillary electrochromatographic analysis of aliphatic mono- and polycarboxylic acids.
abstract: The parameters influencing the electrochromatographic separation of aliphatic organic acids in a capillary column with a wall-coated macrocyclic polyamine have been studied. Indirect detection using chromate, pyromellitate, trimellitate, o-phthalate, benzoate and acetate as background electrolytes has been tested. A complete separation of polyprotic acids could be achieved with pyromellitate buffer (7.5 mM, pH 6.5), and satisfactory results for the simultaneous separation of monoprotic acids and polyprotic acids were found using a capillary column of 70 cm (50 cm effective length)x75 microm inner diameter, electrokinetic injection (-10 kV, 10 s), benzoate buffer (6 mM, pH 4.6), separation voltage of -10 kV, and detection at 220 nm. For the separation of the geometric isomers fumarate and maleate, acetate buffer was found the best choice among the background electrolytes tested. The method so established has been applied to the determination of organic acids in soy sauce, brandy, lemon juice, spinach juice and cigarette. From the retention behavior, it was found that the separation mechanism on the bonded phase was influenced by the macrocyclic effect, electrostatic attraction, hydrogen bonding, van der Waals forces, and anion exchange, in addition to the differences in electrophoretic mobility.
authors.affiliation: Departments of Chemistry, National Taiwan University, Taipei, Taiwan.
authors.forename: Wei-Hsi
authors.initials: WH
authors.lastname: Chen
authors.forename: Chun-Chi
authors.initials: CC
authors.lastname: Lin
authors.forename: Tse-Shien
authors.initials: TS
authors.lastname: Chen
authors.forename: Tarun K
authors.initials: TK
authors.lastname: Misra
authors.forename: Chuen-Ying
authors.initials: CY
authors.lastname: Liu
mesh_terms: D001628:Beverages / Q000032:analysis; D002264:Carboxylic Acids / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D019075:Electrophoresis, Capillary / Q000379:methods*; D005227:Fatty Acids / Q000032:analysis*; D058870:Food, Organic / Q000032:analysis; D006863:Hydrogen-Ion Concentration
chemical_list: D002264:Carboxylic Acids; D005227:Fatty Acids