title: Dynamic pH junction technique for on-line preconcentration of peptides in capillary electrophoresis.
abstract: A method based on the presence of a dynamic pH junction within the capillary to induce band narrowing for enhanced detection sensitivity for some peptides is presented. This technique is predicated on a sharp reduction in an analyte's migration velocity following a reversal of its electrophoretic direction from the acidic sample zone to the basic BGS zone. Larger-than-usual injection volumes of samples in relatively high-conductivity matrices were enabled, without degrading peak shape, resolution and efficiency. The size of the original sample plug was reduced by as much as 38-fold, and improvement in detector response in terms of peak height by as much as 124-fold was obtained. The effects of pH and concentration of the sample matrix, and the length of sample injection on the efficiency of the technique are discussed.
authors.affiliation: Graduate School of Material Science, University of Hyogo, Kamigori, Hyogo 678-1297, Japan. monton@stkt.u-hyogo.ac.jp
authors.forename: Maria Rowena N
authors.initials: MR
authors.lastname: Monton
authors.forename: Koshi
authors.initials: K
authors.lastname: Imami
authors.forename: Machiko
authors.initials: M
authors.lastname: Nakanishi
authors.forename: Jong-Bok
authors.initials: JB
authors.lastname: Kim
authors.forename: Shigeru
authors.initials: S
authors.lastname: Terabe
mesh_terms: D000803:Angiotensin I / Q000302:isolation & purification*; D000804:Angiotensin II / Q000302:isolation & purification*; D002021:Buffers; D019075:Electrophoresis, Capillary / Q000379:methods*; D017022:Flow Injection Analysis; D006863:Hydrogen-Ion Concentration; D010455:Peptides / Q000302:isolation & purification
chemical_list: D002021:Buffers; D010455:Peptides; D000804:Angiotensin II; D000803:Angiotensin I