Abstract: A wide-bore capillary electrophoresis apparatus for the analysis of analyte ions is provided. The apparatus has a wide-bore capillary that has a restriction zone at one or more ends. The capillary has an inlet end and an outlet end and an opening at each of said ends. The restriction zone is capable of providing fluid communication between the wide bore and the opening at said end. The restriction zone includes a narrow bore extending to the opening and a transition zone providing gradual change of bore diameter from the wide bore to the narrow bore. The apparatus further has a buffer source to supply buffer to the inlet end of the capillary and a power supply for supplying power to drive buffer and analyte ions through the capillary. During CE, electrodes provide electrical communication between the power supply and the inlet end and the outlet end and apply a voltage differential between said ends.

Abstract: A microcolumnar analytical apparatus having a flow gating interface system for interfacing a first microcolumn and a second microcolumn is provided. The apparatus includes a flow gating interface, a first fluid conduit (e.g. a liquid chromatograph microcolumn) of a fluid sample, a flush liquid supplier, and a second fluid conduit (e.g. a capillary electrophoresis microcolumn) for analysis of the effluent fluid sample from the first fluid conduit. The flow gating interface includes a first microcolumnar section, a second microcolumnar section, and a channel. The channel, having an inwardly facing wall, encloses at least a portion each of the first microcolumnar section and the second microcolumnar section for conducting a flush fluid flow past the outlet end of the first microcolumnar section and the inlet end of the second microcolumnar section.

Abstract: A flow gating interface system including a first microcolumnar section, a second microcolumnar section, and a channel for interfacing a first fluid conduit and a second fluid conduit is provided. The channel, having an inwardly facing wall, encloses at least a portion each of the first microcolumnar section and the second microcolumnar section for conducting a flush fluid flow past the outlet end of the first microcolumnar section and the inlet end of the second microcolumnar section. The inwardly facing wall of the channel nonfixedly constrains and aligns the end portions of the first and second microcolumnar sections. The outlet end of the first fluid conduit is connected to and in fluid communication with the first microcolumnar section of the flow gating interface. The inlet end of the second fluid conduit is connected to and in fluid communication with the second microcolumnar section of the flow gating interface.

Abstract: A system for controlling the bulk flow rate in capillary electrophoresis employs pressure to increase velocity without unacceptably increasing plate height. Thus, the system controls bulk flow over a range of velocities, independent of the chemistry of the system. Additionally, the use of pressure under certain conditions may decrease plate height and improve resolution.

Abstract: In accordance with the present invention, a compliant pressure differential is applied across a separation column while its inlet is in a sample solution so that sample solution is introduced into the column. The profile of pressure differential over time is selected so that a desired volume of sample solution is introduced. Pressure and time are controlled with sufficient precision to yield repeatability of 5%, and preferably within 1%, by volume. The pressure differential is sufficiently low and the time sufficiently long that an acceptable velocity profile can be achieved.

Abstract: In accordance with the present invention, a compliant pressure differential is applied across a separation column while its inlet is in a sample solution so that sample solution is introduced into the column. The profile of pressure differential over time is selected so that a desired volume of sample solution is introduced. Pressure and time are controlled with sufficient precision to yield repeatability of within 5%, and preferably within 1%, by volume. The pressure differential is sufficiently low and the time sufficiently long that an acceptable velocity profile can be achieved.

Abstract: An electrophoretic apparatus that is useful for separation of analytes, such as proteins, comprises a capillary tube that has an interfacial layer bonded to reduce interactions between the bore and analytes during electroosmotic flow through the capillary, and an electrically modified media carried by or contacting a capillary wall outward from the bore. The modified media can be an electrically resistive coating or an electrically conductive coating. Together with appropriate power supply configurations, the electrically modified media permits the application of a voltage gradient that is transverse to the electrophoretic gradient, and provides electroosmotic flow control in cooperation with the interfacial layer.

Abstract: A system and method for controlling the rate of electroosmotic flow in capillary electrophoresis. A first high voltage power supply is electrically connected to the inlet end of a capillary tube, while a second high voltage power supply is connected at an outlet end. The potential difference across the capillary tube is therefore the difference between the high voltages. Electroosmotic flow can be controlled by varying the two high voltages correspondingly to maintain the same potential difference but to achieve a different voltage offset relative to ground. Optionally, the voltage offset may be varied during electrophoresis analysis to slow migration during periods in which constituents are closely spaced and to speed migration when constituents are sufficiently spaced apart. A conductive capillary tube coating which is preferably grounded defines an external control area for electroosmotic flow. A detector is located downstream of the external control area, so that the coating is a unitary layer.

Abstract: An apparatus for electrophoretic separation comprising a fixed support structure and a cassette shell which is removably attached to the support device. Within the cassette shell is a basket having symmetrically arranged ribs to secure a capillary tube in a helical configuration. The ribs have notches to receive a loop of the helically wound capillary tube. The notches of the ribs alternate in orientation with respect to the axis of the helically wound capillary tube. A quarter-turn locking member provides electrical, optical and coolant fluid communication between the cassette shell and the support device.

Abstract: An X-Y recorder for high speed plotting on a plain web, i.e., a web without registration holes or other special means to maintain alignment of the web during plotting. Two embodiments of these plotters are disclosed with one degree of motion being achieved by moving the web and the second degree of motion being obtained by moving a pen assembly substantially perpendicularly to the movement of the web. To enhance the repeatability of the plotting on the web as it is moved back and forth, a random rough surfaced drive wheel assembly is included with that wheel surface making indentations along one surface of the driven edge of the web as it is first passed through the drive wheel assembly. Then as the web is reversed, these indentations substantially remesh with the random rough surface of the drive wheels.

Abstract: An electron capture detector in which a thermionic source such as a filament provides electrons for the reaction in a source chamber having a port that connects to a detection chamber having a collector. Guard gas is introduced into the source chamber and sample gas into the detection chamber, and an exhaust port is provided in the detection chamber.

Abstract: An electron capture detector in which electrons for the reaction are supplied by a filament in a cylinder through which guard gas is passed. Apertures in the cylinder permit electrons from the filament to pass into an annular space surrounding the cylinder and between it and a collector. Sample gas is passed between the aperture and the collector, the pressures being such as to be capable of minimizing the diffusion of sample gas to the filament.

Abstract: A pumping system is provided in which a low pressure metering pump injects fluid charges into a high pressure pump which in turn operates into a high pressure load. The high pressure pump is designed to always present a low pressure at its input on its intake stroke. This insures that the metering pump will always operate into a low pressure regardless of the load, and will therefore be enabled to always accurately meter charges into the high pressure pump.In various embodiments, the high pressure pump and/or the low pressure pump include spring elements for providing well defined pumping pressures.In some embodiments, an oil reservoir and diaphragm provide a well defined pressure against which the metering pump can operate.