Abstract: In a method for controlling sample introduction in microcolumn separation techniques, more particularly in capillary electrophoresis (CE), where a sample is injected as a sample plug into a sampling device which comprises at least a channel for the electrolyte buffer and a supply and drain channel for the sample. The supply and drain channels discharge into the electolyte channel at respective supply and drain ports. The distance between the supply port and the drain port geometrically defines a sample volume. The injection of the sample plug into the electrolyte channel is accomplished electrokinetically by applying an electric field across the supply and drain channels for a time at least long enough that the sample component having the lowest electrophoretic mobility is contained within the geometrically defined volume. The supply and drain channels each are inclined to the electrolyte channel. Means are provided for electrokinetically injecting the sample into the sample volume.

Abstract: In a method for controlling sample introduction in microcolumn separation techniques, more particularly in capillary electrophoresis (CE), where a sample is injected as a sample plug into a sampling device which comprises at least a channel for the electrolyte buffer and a supply and drain channel for the sample. The supply and drain channels discharge into the electolyte channel at respective supply and drain ports. The distance between the supply port and the drain port geometrically defines a sample volume. The injection of the sample plug into the electrolyte channel is accomplished electrokinetically by applying an electric field across the supply and drain channels for a time at least long enough that the sample component having the lowest electrophoretic mobility is contained within the geometrically defined volume. The supply and drain channels each are inclined to the electrolyte channel. Means are provided for electrokinetically injecting the sample into the sample volume.

Abstract: In a method for controlling sample introduction in microcolumn separation techniques, more particularly in capillary electrophoresis (CE), where a sample is injected as a sample plug into a sampling device which comprises at least a channel for the electrolyte buffer and a supply and drain channel for the sample. The supply and drain channels discharge into the electolyte channel at respective supply and drain ports. The distance between the supply port and the drain port geometrically defines a sample volume. The injection of the sample plug into the electrolyte channel is accomplished electrokinetically by applying an electric field across the supply and drain channels for a time at least long enough that the sample component having the lowest electrophoretic mobility is contained within the geometrically defined volume. The supply and drain channels each are inclined to the electrolyte channel. Means are provided for electrokinetically injecting the sample into the sample volume.

Abstract: In a method for controlling sample introduction in microcolumn separation techniques, more particularly in capillary electrophoresis (CE), where a sample is injected as a sample plug into a sampling device which comprises at least a channel for the electrolyte buffer and a supply and drain channel for the sample. The supply and drain channels discharge into the electolyte channel at respective supply and drain ports. The distance between the supply port and the drain port geometrically defines a sample volume. The injection of the sample plug into the electrolyte channel is accomplished electrokinetically by applying an electric field across the supply and drain channels for a time at least long enough that the sample component having the lowest electrophoretic mobility is contained within the geometrically defined volume. The supply and drain channels each are inclined to the electrolyte channel. Means are provided for electrokinetically injecting the sample into the sample volume.

Abstract: In a method for controlling sample introduction in microcolumn separation techniques, more particularly in capillary electrophoresis (CE), where a sample is injected as a sample plug into a sampling device which comprises at least a channel for the electrolyte buffer and a supply and drain channel for the sample. The supply and drain channels discharge into the electolyte channel at respective supply and drain ports. The distance between the supply port and the drain port geometrically defines a sample volume. The injection of the sample plug into the electrolyte channel is accomplished electrokinetically by applying an electric field across the supply and drain channels for a time at least long enough that the sample component having the lowest electrophoretic mobility is contained within the geometrically defined volume. The supply and drain channels each are inclined to the electrolyte channel. Means are provided for electrokinetically injecting the sample into the sample volume.

Abstract: In a method for controlling sample introduction in microcolumn separation techniques, more particularly in capillary electrophoresis (CE), where a sample is injected as a sample plug into a sampling device which comprises at least a channel for the electrolyte buffer and a supply and drain channel for the sample. The supply and drain channels discharge into the electolyte channel at respective supply and drain ports. The distance between the supply port and the drain port geometrically defines a sample volume. The injection of the sample plug into the electrolyte channel is accomplished electrokinetically by applying an electric field across the supply and drain channels for a time at least long enough that the sample component having the lowest electrophoretic mobility is contained within the geometrically defined volume. The supply and drain channels each are inclined to the electrolyte channel. Means are provided for electrokinetically injecting the sample into the sample volume.

Abstract: In a method for controlling sample introduction in microcolumn separation techniques, more particularly in capillary electrophoresis (CE), where a sample is injected as a sample plug into a sampling device which comprises at least a channel for the electrolyte buffer and a supply and drain channel for the sample. The supply and drain channels discharge into the electrolyte channel at respective supply and drain ports. The distance between the supply port and the drain port geometrically defines a sample volume. The injection of the sample plug into the electrolyte channel is accomplished electrokinetically by applying an electric field across the supply and drain channels for a time at least long enough that the sample component having the lowest electrophoretic mobility is contained within the geometrically defined volume. The supply and drain channels each are inclined to the electrolyte channel. Means are provided for electrokinetically injecting the sample into the sample volume.

Abstract: In a method for controlling sample introduction in microcolumn separation techniques, more particularly in capillary electrophoresis (CE), where a sample is injected as a sample plug into a sampling device which comprises at least a channel for the electrolyte buffer and a supply and drain channel for the sample. The supply and drain channels discharge into the electolyte channel at respective supply and drain ports. The distance between the supply port and the drain port geometrically defines a sample volume. The injection of the sample plug into the electrolyte channel is accomplished electrokinetically by applying an electric field across the supply and drain channels for a time at least long enough that the sample component having the lowest electrophoretic mobility is contained within the geometrically defined volume. The supply and drain channels each are inclined to the electrolyte channel. Means are provided for electrokinetically injecting the sample into the sample volume.

Abstract: An improved absorbance or detection cell for a microfluid device, and in accordance with an aspect of the invention, the absorbance cell comprises a bottom plate having a channel bearing surface in which a channel having a fluid inlet and fluid outlet is defined, a top plate having a channel facing surface bound to the channel bearing surface of the bottom plate and first and second reflecting elements formed on opposed sides of the channel to form a waveguide through which the channel extends such that radiation propagating along the waveguide makes multiple passes across the channel, the waveguide having a radiation input end and a radiation output end.