title: Microchip-based capillary electrochromatography using packed beds.
abstract: Integration of a packed column onto a microchip for performance of capillary electrochromatography (CEC) is described. The quartz device incorporated a cross-injector, and a double weir trapping design for formation of 1, 2 and 5 mm long CEC columns. Three fluorescent dyes were baseline-resolved with plate numbers of 330,(330,000 plates/m; height equivalent to a theoretical plate, H = 3.0 microm) for BODIPY 493/503, 360 (360,000 plates/m; H = 2.8 microm) for rhodamine 123 and 244 (244,000 plates/m; H = 4.1 microm) for acridine orange (AO) with 500 V applied on a 1 mm long column. The 2 mm column yielded approximately 1.8 times more theoretical plates than did the 1 mm column, when operated at the same flow rate. Van Deemter plots were obtained for the three column lengths, showing increased plate height for the 5 mm length. A 2 mm column gave peak height and area relative standard deviation (RSD) values of 2.5 and 3.3%, respectively, as averages for the three dyes (n = 15). The RSD for the dye retention times was 1% (n = 6) over one day, and 3% (n = 30) over five days. Indirect fluorescence detection of thiourea and of amino acids was possible using a neutral indicator dye (BODIPY 493/503), with a detection limit of 10 microM for amino acids.
authors.affiliation: Department of Chemistry, University of Alberta, Edmonton, AB, Canada.
authors.forename: Abebaw B
authors.initials: AB
authors.lastname: Jemere
authors.forename: Richard D
authors.initials: RD
authors.lastname: Oleschuk
authors.forename: D Jed
authors.initials: DJ
authors.lastname: Harrison
mesh_terms: D001120:Arginine / Q000032:analysis; D001896:Boron Compounds; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D005456:Fluorescent Dyes; D007834:Lasers; D007930:Leucine / Q000032:analysis; D008689:Methacrylates / Q000737:chemistry; D008863:Microspheres; D011108:Polymers / Q000737:chemistry; D015203:Reproducibility of Results; D012822:Silicon Dioxide; D013890:Thiourea / Q000032:analysis; D013997:Time Factors
chemical_list: C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D005456:Fluorescent Dyes; D008689:Methacrylates; D011108:Polymers; D012822:Silicon Dioxide; C042953:octadecyl silane-bonded silica; D001120:Arginine; D007930:Leucine; D013890:Thiourea