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An integrated solid-phase extraction system for sub-picomolar detection.

Abebaw Belay Jemere·Richard D Oleschuk·Fahima Ouchen·Festus Fajuyigbe·D Jed Harrison
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Abstract

A microchip structure etched on a glass substrate for packed column solid-phase extraction (SPE) and capillary electrochromatography (CEC) is described. A 200 microm long, octadecylsilane (ODS) packed column was secured using two different approaches: solvent lock or polymer entrapment. The former method was utilized for SPE while the latter approach was applied for CEC. In SPE, the ODS packed chamber gave a detection limit of 70 fM for a nonpolar BODIPY (493/503) dye when concentrated for 3 min at an electroosmotic flow rate of 4.14 nL/min, compared to 30 pM for this detector without the SPE step. SPE beds showed reproducible, linear calibration curves (R(2) = 0.9989) between 1 and 100 pM BODIPY at fixed preconcentration times. Breakthrough curves for the 330 pL (ODS-packed) bed indicated a capacity for BODIPY dye of 8.1 x 10(-14) mmol, or 0.25 mmol dye per liter of bed. The ODS-chamber could also be used to analyze dilute amino acid and peptide solutions. In the CEC format, two neutral dyes (BODIPY and acridine orange) were baseline-separated in an isocratic run with a theoretical plate count of 84 (420 000 plates/m) and a reduced plate height of about 1. A labeled peptide was also analyzed by CEC, using the acidic eluent (84% acetonitrile, and 26% aqueous trifluoroacetic acid (0.05%)) preferred for peptide separations on ODS-coated silica particles.

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Acridine OrangeAmino AcidsBoron CompoundsChemical FractionationElectrophoresis, CapillaryEquipment DesignMiniaturizationJournal ArticleResearch Support, Non-U.S. Gov't

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Abebaw Belay Jemere, Richard D Oleschuk, Fahima Ouchen, Festus Fajuyigbe, D Jed Harrison. 2002. An integrated solid-phase extraction system for sub-picomolar detection.. https://doi.org/10.1002/1522-2683(200210)23%3A20%3C3537%3A%3Aaid-elps3537%3E3.0.co%3B2-9

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