title: Multiple capillary isotachophoresis with repetitive hydrodynamic injections for performance improvement of the electromigration preconcentration.
abstract: A novel electrokinetic preconcentration technique based on multiple isotachophoresis (M-ITP) realised in a micro-bored capillary to improve sensitivity for capillary electrophoresis with hydrodynamic injection was developed. The M-ITP operation relies on pressure-assisted pushing of a preconcentrated sample plug after the first ITP process back to the injection end of the capillary, followed by a large volume hydrodynamic injection prior to application of the second ITP step. This operational cycle was repeated as many times as desired with very good repeatability of the peak areas and peak heights at each ITP round (RSD less than 8%). Using imidazole and benzoate as models for cationic and anionic analytes, important insights into the mechanism of this electrokinetic preconcentration process with and without the presence of the electro-osmotic flow (EOF) at acidic and basic conditions were provided. Stacking of the benzoate ion, selected as one model analyte, in the presence of EOF and from a sample plug representing up to 300% of the total capillary length was successfully demonstrated. M-ITP was then demonstrated through the enrichment of the Aβ 1-40 amyloid peptide, considered as one of the biomarkers for biochemical diagnosis of Alzheimer's disease. Quantification of Aβ 1-40 down to 50nM with UV detection was made possible with 6 M-ITP cycles.
authors.affiliation: Institut Galien Paris Sud, UMR8612, Protein and Nanotechnology in Analytical Science (PNAS), CNRS, Univ. Paris-Sud, Université Paris-Saclay, 5 rue Jean Baptiste Clément, 92290 Châtenay-Malabry, France.
authors.forename: Thanh Duc
authors.initials: TD
authors.lastname: Mai
authors.affiliation: Université Grenoble Alpes, CNRS, DPM UMR 5063, F-38041 Grenoble, France.
authors.forename: Farid
authors.initials: F
authors.lastname: Oukacine
authors.affiliation: Institut Galien Paris Sud, UMR8612, Protein and Nanotechnology in Analytical Science (PNAS), CNRS, Univ. Paris-Sud, Université Paris-Saclay, 5 rue Jean Baptiste Clément, 92290 Châtenay-Malabry, France. Electronic address: myriam.taverna@u-psud.fr.
authors.forename: Myriam
authors.initials: M
authors.lastname: Taverna
mesh_terms: D019817:Benzoic Acid / Q000737:chemistry; D019075:Electrophoresis, Capillary / Q000379:methods; D006801:Humans; D057446:Hydrodynamics; D007093:Imidazoles / Q000737:chemistry; D007477:Ions; D057625:Isotachophoresis / Q000379:methods*
chemical_list: D007093:Imidazoles; D007477:Ions; C029899:imidazole; D019817:Benzoic Acid
keywords: Amyloid peptides; Capillary electrophoresis (CE); Electrokinetic preconcentration; Multiple-isotachophoresis (M-ITP)