Selected Organic Solvents as Electroosmotic Velocity Markers in Micellar Electrokinetic Capillary Chromatography

Abstract

This study examines typical organic solvents which may be used for analyte dissolution and as reference solvent for determination of electroosmotic velocity. Five solvents were investigated: acetone, acetonitrile, methanol, l-propanol, and tetrahydrofuran at SDS concentrations of 40, 60, 80, 100, and 120 mM. A precise method for measuring electroosmotic velocity is presented which minimizes run to run variations and yields electroosmotic velocities that are reproducible. Tetrahydrofuran exhibits the greatest electroosmotic velocity at 40 mM SDS, while 1-propanol has the lowest electroosmotic velocity at 40 mM SDS. Acetone, acetonitrile, and methanol are determined to have electroosmotic velocities that are approximately the same at 40 mM SDS. At 60,80, 100, and 120 mM SDS the migration velocity of each of the five solvents decreased linearly under our operating conditions and are approximately the same at each of these SDS concentrations.