title: Very fast electrophoretic separation on commercial instruments using a combination of two capillaries with different internal diameters.
abstract: A capillary formed by connecting a 9.7 cm-long separation capillary with id 25 μm with an auxiliary 22.9 cm-long capillary with id 100 μm (coupled capillary) was tested for electrophoretic separation at high electric field intensities. The coupled capillary was placed in the cassette of a standard electrophoresis apparatus. It was used in the short-end injection mode for separation of a mixture of dopamine, noradrenaline, and adrenaline in a BGE of 20 mM citric acid/NaOH, pH 3.2. An intensity of 2.7 kV/cm was attained in the separation part of the capillary at a separation voltage of 30 kV, which is 2.9 times more than maximum intensity value attainable in a capillary with the same length with uniform id. At these high electric field intensities, the migration times of the tested neurotransmitters had values of 12.3-13.3 s and the attained separation efficiency was between 2350 and 2760 plates/s. It is thus demonstrated that an effective separation instrument - a coupled capillary - can be used for very rapid separation in combination with standard, commercially available instrumentation.
authors.affiliation: Institute of Biochemistry, Cell and Molecular Biology, Third Faculty of Medicine, Charles University in Prague, Prague, Czech Republic. petr.tuma@lf3.cuni.cz
authors.forename: Petr
authors.initials: P
authors.lastname: Tůma
authors.forename: František
authors.initials: F
authors.lastname: Opekar
authors.forename: Eva
authors.initials: E
authors.lastname: Samcová
mesh_terms: D002395:Catecholamines / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D019343:Citric Acid / Q000737:chemistry; D019075:Electrophoresis, Capillary / Q000295:instrumentation* / Q000379:methods*; D008956:Models, Chemical; D018377:Neurotransmitter Agents / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D012972:Sodium Hydroxide / Q000737:chemistry; D013997:Time Factors
chemical_list: D002395:Catecholamines; D018377:Neurotransmitter Agents; D019343:Citric Acid; D012972:Sodium Hydroxide