title: Electrolyte system strategies for anionic isotachophoresis with electrospray-ionization mass-spectrometric detection. 2. Isotachophoresis in moving-boundary systems.
abstract: This contribution is the second part of the project on strategies used in the selection of electrolyte systems for anionic ITP with ESI-mass spectrometric detection. It presents ITP as a powerful tool for selective stacking of anionic analytes, performed in a nonconventional way in moving-boundary systems where two co-anions are present in both the leading and terminating zones. The theoretical background is given to substantiate the conditions for the existence and migration of ITP boundaries in moving-boundary systems and stacking of analytes at these boundaries. The practical aspects of the theory are shown in form of stacking-window diagrams that bring immediate information about which analytes are stacked in a given system. The presented theory and strategy are illustrated and verified on the example of analysis of a model mixture of salicylic acid, ibuprofen and diclofenac, and comparison of regular and free-acid ITP with moving-boundary ITP systems formed by formic and propionic acids and ammonium as counterion.
authors.affiliation: Institute of Analytical Chemistry of the Academy of Sciences of the Czech Republic, v.v.i, Brno, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Gebauer
authors.forename: Zdena
authors.initials: Z
authors.lastname: Malá
authors.forename: Petr
authors.initials: P
authors.lastname: Boček
mesh_terms: D006863:Hydrogen-Ion Concentration; D057625:Isotachophoresis / Q000379:methods*; D008956:Models, Chemical; D004364:Pharmaceutical Preparations / Q000737:chemistry / Q000302:isolation & purification; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D004364:Pharmaceutical Preparations
keywords: ESI-MS detection; Electrolyte systems; Isotachophoresis; Moving-boundary electrophoresis; Pharmaceuticals