title: ITP in dynamically double-coated fused-silica capillaries.
abstract: Bidirectional ITP in fused-silica capillaries double-coated with Polybrene and poly-(vinylsulfonate) is a robust approach for analysis of low-molecular-mass compounds. EOF towards the cathode is strong (mobility >4.0 x 10(-8) m(2)/Vs) within the entire pH range investigated (2.40-8.08), dependent on ionic strength and buffer used and, at constant ionic strength, higher at alkaline pH. Electrokinetic separations and transport in such coated capillaries can be described with a dynamic computer model which permits the combined simulation of electrophoresis and electroosmosis in which the EOF is predicted either with a constant (i.e. pH- and ionic strength-independent) or a pH- and ionic strength-dependent electroosmotic mobility. Detector profiles predicted by computer simulation agree qualitatively well with bidirectional isotachopherograms that are monitored with a setup comprising two axial contactless conductivity detectors and a UV absorbance detector. The varying EOF predicted with a pH- and ionic strength-dependent electroosmotic mobility can be regarded as being realistic.
authors.affiliation: Department of Clinical Pharmacology, University of Bern, Bern, Switzerland.
authors.forename: Jitka
authors.initials: J
authors.lastname: Caslavska
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Thormann
mesh_terms: D000143:Acids / Q000737:chemistry; D003198:Computer Simulation; D019075:Electrophoresis, Capillary / Q000379:methods* / Q000592:standards*; D006583:Hexadimethrine Bromide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D009995:Osmosis; D011145:Polyvinyls / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D013451:Sulfonic Acids / Q000737:chemistry
chemical_list: D000143:Acids; D011145:Polyvinyls; D013451:Sulfonic Acids; C008959:lyapolate; D006583:Hexadimethrine Bromide; D012822:Silicon Dioxide