Chromatographic columns, particularly liquid chromatographic columns, have provided for the employment of an electrically conductive, stationary solid phase, and the preferential interaction of solutes in a fluid to be chromatographically separated with the solid, stationary phase, such as set forth in "Electrically Conductive Stationary Phases for HPLC".sup.1 issued by Barbara Bassler and Richard Hartwick, Abstract from the AICHE Meeting, San Francisco, Calif., Nov. 5-10, 1989, and in "Electrochromatography - A Preliminary Study of the Effect of Applied Potential On A Carbonaceous Chromatographic Column".sup.2, by Robert Antrim, Robert Scherrer and Alexander Yacynych, Anal. Chim. Acta., 164 (1984) 283. The above references describe an electron rich, porous, graphitic, carbon, stationary phase to act as a controlled potential surface to affect the resolution of solutes to be chromatographed in both polar and non-polar solvents. In such chromatographic columns as HPLC, the conductive packing is employed as one electrode and the surrounding metal tube of the column as the other electrode. These columns do not act as capacitors, since the voltage drop is generally entirely across the metal tube and insignificant across the claimed controlled potential surface to be modulated, so that little electrostatic absorption occurs.
In addition, electrically conductive stationary phases have been employed to deposit and strip solutes via electrolysis, see for example, "Continuous Quantitative Electrolysis".sup.3, W. J. Blaedel and J. H. Strohl, Anal. Chem., Vol. 36, No. 7, June, 1964; "A Packed Graphite Cell For Thin Layer Electrochemistry".sup.4, John Strohl and Thomas Polutanovich, Analytical Letters, 2(8), pp. 423-431 (1969); "Electrolytic Chromatography and Coulometric Detection With the Column Electrode".sup.5, Taitiro Fujinaga, Pure Applied Chemistry, 25 (1971) pp. 709-726; and "Modified Graphites for Chelation and Ion Exchange".sup.6, James Hern and John H. Strohl, Analytical Chemistry, Vol. 50, No. 14, December, 1978. In addition, capacitance techniques have been employed for the absorption of blood proteins on metals, as set forth by G. Stoner and S. Srinivasan, "Absorbtion of Blood Proteins on Metals Using Capacitance Techniques".sup.7, Journal of Physical Chemistry, Vol. 74, No. 5, pp. 1088-1094, Mar. 5, 1970. While electrolysis devices have been used to purify solutions, the devices affect purification by deposition and stripping electrochemically the material and not by electrostatic absorption.
U.S. Pat. No. 4,769,1918, issued Sep. 6, 1988, describes an anode electrode of an electrolytic capacitor having a biochemically active layer embedded in the pores of the electrodes and that the electrodes change electrical properties by the presence of the chemical layers. This patent discloses using a biochemical layer and wherein analyte molecules replace other molecules from the biochemically active layer to effect the change in the dielectric properties of the electrodes, and this change is employed to measure the concentration of analyte molecules.
None of the above prior art references describe a device which affects absorption or resolution of solutes to be chromatographed via a high capacitance, combined with a flow-through configuration to allow the capacitor to function as a chromatographic system. It is desirable to provide for controlled charge chromatography system and method which employs a flow-through capacitor of high surface area material for both anode and cathode, to provide for a high efficiency, effective purifying system to modulate the absorption and/or resolution of ions and non-ionic solutes in polar and non-polar solvents.
USPTO Backgrounds
USPTO Backgrounds