This paper evaluates various sample preparation methods for multicapillary gel electrophoresis based glycan analysis to support electrokinetic injection. First the removal of excess derivatization reagent is discussed. Although the Sephadex G10 filled multiscreen 96-well filter plate and Sephadex G10 filled pipet tips enabled increased analysis sensitivity, polyamide DPA-6S pipet tips worked pa...

Field-enhanced sample stacking, field-enhanced sample injection as well as electrokinetic supercharging have been successfully integrated in carrier ampholyte-based capillary electrophoresis. Through the analysis of different test sample mixtures, it has been shown that the carrier ampholyte-based background electrolytes, in spite of their very low conductivity, allow efficient online preconcen...

Derivatization is a frequently used sample preparation procedure applicable to the enhancement of analyte detection sensitivity. Amino acids mostly require derivatization prior to electrophoretic or chromatographic analysis, especially if spectrophotometric detection is used. This study presents an on-line preconcentration technique for derivatized amino acids. The sensitivity of the method was...

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Laser-patterning of nanoporous membranes at the junction of a cross channel in a microchip is used to integrate protein concentration with an electrokinetic injection scheme. Upon application of voltage, linear electrophoretic concentration of charged proteins is achieved at the membrane surface because buffer ions can easily pass through the membrane while proteins larger than the molecular we...

A rapid and sensitive method using pressure-assisted electrokinetic injection (PAEKI) as the on-line sample enrichment technique and electrospray-tandem mass spectrometry as the monitor has been developed for the determination of four halogenated phenols, 2,4,6-trichlorophenol, 2,4-dichlorophenol, 2,3,4,6-tetrachlorophenol and tetrabromobisphenol A, in water samples. In 8-min of injection, the ...

We present a microfluidic sample introduction approach based on a novel flow control mechanism, hydrodynamic gated injection. It has the advantages of easy and flexible flow control, similar to its analog, electrokinetic gated injection, but exhibits the unique properties of strong driving force and good biocompatibility, ideal for applications involving live biological samples. Theories for hy...