title: Nanoparticle-based continuous full filling capillary electrochromatography/electrospray ionization-mass spectrometry for separation of neutral compounds.
abstract: Highly efficient reversed-phase capillary electrochromatography (CEC) separations (plate numbers up to 700 000/m), with electrospray ionization mass spectrometry detection were achieved utilizing novel dextran-coated polymer nanoparticles as a pseudostationary phase. A continuous full filling (CFF) technique in which nanoparticles are continuously introduced into the capillary was employed for separation of neutral analytes (dialkyl phthalates), utilizing an orthogonal electrospray interface to prevent nanoparticles from entering the mass spectrometer. CFF-CEC benefits from that an entirely fresh column is employed for every analysis, avoiding carryover effects associated with stationary-phase contamination. The highly efficient separations obtained were accomplished by optimizing the organic modifier concentration in the electrolyte and by using a high nanoparticle concentration (5 mg/mL), to improve interparticle mass transfer and gain sufficient retention. Nanoparticles, with an average diameter of 600 nm, were prepared by polymerization of methacrylic acid and trimethylolpropane trimethacrylate, which in turn were coated with dextran. These nanoparticles formed stable suspensions in electrolytes having broad ranges of polarities, enabling straightforward optimization of the reversed-phase conditions.
authors.affiliation: Pure and Applied Biochemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, 221 00 Lund, Sweden.
authors.forename: Christian
authors.initials: C
authors.lastname: Nilsson
authors.forename: Peter
authors.initials: P
authors.lastname: Viberg
authors.forename: Peter
authors.initials: P
authors.lastname: Spégel
authors.forename: Magnus
authors.initials: M
authors.lastname: Jörntén-Karlsson
authors.forename: Patrik
authors.initials: P
authors.lastname: Petersson
authors.forename: Staffan
authors.initials: S
authors.lastname: Nilsson
mesh_terms: D053801:Capillary Electrochromatography / Q000379:methods*; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013499:Surface Properties