Electrokinetics 724 INDEX

Kovat s retention index (p. 575) liquid-solid adsorption chromatography (p. 590) longitudinal diffusion (p. 560) loop injector (p. 584) mass spectrum (p. 571) mass transfer (p. 561) micellar electrokinetic capillary chromatography (p. 606) micelle (p. 606) mobile phase (p. 546) normal-phase chromatography (p. 580) on-column injection (p. 568) open tubular column (p. 564) packed column (p. 564) peak capacity (p. 554)... 

A hydrophobidty scale based on the migration index from emulsion electrokinetic chromatography of anionic solutes. Anal. Chem. 1996, 68, 1028-1032. 

Research has been done showing that rapid pressnre-driven LC analysis can be done with little solvent consumption, demonstrating this as a viable process analytical tool. Using electrokinetic nanoflow pumps LC can be miniaturized to the point of being a sensor system. Developments in terms of sampling to enable sampling directly from a process stream, to the separation channel on a chip are critical for the application of miniaturized process LC. The components (valves and pumps) required for hydrodynamic flow systems appear to be a current limitation to the fnll miniatnrization of LC separations. Detection systems have also evolved with electrochemical detection and refractive index detection systems providing increased sensitivity in miniaturized systems when compared to standard UV-vis detection or fluorescence, which may require precolumn derivatization. 

PG Muijselaar, HA Claessens, CA Cramers. Characterization of pseudostation-ary phases in micellar electrokinetic chromatography by applying linear solvation-energy relationships and retention indexes. Anal. Chem. 69 1184—1191... 

PGHM Muijselaar, HA Claessens, CA Cramers. Application of the retention index concept in micellar electrokinetic capillary chromatography. Anal Chem 66 635-644, 1994. 

From this retention factor, the Migration Index (MI) for a compound in microemulsion electrokinetic chromatography was defined as [Ishihama, Oda et al., 1996]... 

Fatemi, M.H. (2003) Quantitative structure-property relationship studies of migration index in microemulsion electrokinetic chromatography using artificial neural networks./. Chromat., 1002, 221-229. 

Evanescent wave microscopy has already yielded a number of contributions to the fields of micro-and nanoscale fluid and mass transport, including investigation of the no-slip boundary condition, applications to electrokinetic flows, and verification of hindered Brownian motion. With more experimental data and improvements to TIRE techniques, the accuracy and resolution of these techniques are certain to improve. Areas of potential improvements include development of rmiform-sized and bright tracer particles, creation of high-NA imaging optics and high-sensitivity camera systems, and further development of variable index materials for better control of the penetration-depth characteristics. 

The list could be made longer, taking the idea of electrokinetics in a wide sense (response of the colloidal system to an external field that affects differently to particles and liquid). Thus, we could include electroviscous effects (the presence of the EDL alters the viscosity of a suspension in the Newtonian range) suspension conductivity (the effect of the solid-liquid interface on the direct current (DC) conductivity of the suspension) particle electroorientation (the torque exerted by an external field on anisotropic particles will provoke their orientation this affects the refractive index of the suspension, and its variation, if it is alternating, is related to the double-layer characteristics). 

Electrokinetic biofence (EBF) consists of a row of alternating cathodes and anodes with a mutual distance of 5 m. Upstream of the line of electrodes, a series of infiltration wells were installed, which have been periodically filled with nutrients. The aim of the EBF is to enhance biodegradation of the VOCs in the groundwater at the zone of the fence by electrokinetic dispersion of the dissolved nutrients in the groundwater. After running the EBF for nearly 2 years, clear results have been observed. The concentration of nutrients in the zone has increased, the chloride index is decreasing, and VOCs are being dechlorinated by bioactivity. 

The range of available active and passive optical materials is much too extensive to be described in detail and thus we will focus on the handful which are of broadest interest to optofluidics and separate them into those which are usable in the infrared and visible spectra. Within the former of these silicon specifically, silicon on insulator, tends to be the material of choice, primarily due to the well developed fabrication procedures, simplicity of integration with electronics and high refractive index. The underlying oxide layer serves to isolate the optical components but also as a convenient surface for biochemical functionalization. While generally compatible with most fluids, the conductivity of silicon can lead to some difficulties with electrically driven flow mechanisms such as electrokinetics. 

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