Abstract: The present invention pertains to a liquid chromatography method of separating multicharged ions, and more particularly, to separating both positively charged and negatively charged ions by using a mobile phase composition with doubly charged ions and an ion-exchange column with a charged stationary phase surface.

Abstract: Disclosed is a HPLC system including a first dimension column, a second dimension column, a high pressure switching valve installed along the mobile phase flow path with the usual detector. At a predetermined time after injection of a sample into the mobile phase stream, the valve is actuated so that late eluted components, while still in the first dimension column, are back-flushed to waste by the flow of mobile phase while the analytes get separated in the second dimension column. Mixed-mode cation exchange and anion exchange columns are particularly suited for this application.

Abstract: A disposable chromatography sample introduction device includes a stylus with a holder and a tubular stem extending from one end of the holder containing porous sample-holding material. The stylus has a pair of spaced openings permitting fluid flow therethrough. An injector housing includes an insertion port for receiving the stylus, a seal, an inlet port for communicating with one stylus opening, and an outlet port for communicating with the other stylus opening. When the stem is immersed in a sample, sample enters the stem by capillary action. Thereafter, the stylus is inserted into the housing insertion port where mobile phase flowing from inlet port to outlet port passes through the stem extracting sample. The holder has a finger grip and an external thread that engages a complementary injector housing thread to secure the holder when the stylus is inserted therein.

Abstract: A pump for use in high pressure liquid chromatography includes a housing with a pump head at one end and an axially-movable, high-pressure piston with a small-diameter plunger reciprocating within the pump head to move fluid from an inlet through an outlet at high pressure. An attached motor rotates a circular cam fixed off center on the motor shaft to reciprocate the piston that has an inner end in engaging contact with the cam periphery. An axially-aligned, torque-compensating piston is provided and has an inner end biased by spring force against the cam opposite the high-pressure piston. A large-diameter piston head may be fixed to the outer end of the torque-compensating piston and slidably mounted within a cylinder defined at the housing end opposite the pump head. The outer end of the piston head is open to ambient atmosphere.

Abstract: A fitting for holding a tube in fluid communication with a cooperating component having a port with an internal thread of preselected pitch includes a coupling body with a longitudinal bore for receiving the tube, a grippable portion, and radially displaceable, tube clamping fingers separated by longitudinal slots. An external thread is defined on the surface of the fingers and is engageable with the internal thread of the port. The external thread has a pitch diameter similar to the pitch diameter of the internal thread and a pitch dissimilar to the pitch of the internal thread. Rotation of the fitting relative to the component to engage the threads effects relative axial movement thereof and radial displacement of the fingers into clamping engagement with the tube to hold it within the fitting. A sealing end ferrule may be included on the forward end of the coupling body.

Abstract: A magnetic reciprocating pump includes a tube having ends defining intake and discharge ports, first and second magnetic plungers axially aligned within the tube of corresponding cross section for reciprocation therewithin, and a plurality of longitudinally spaced coils circumscribing the tube for driving the plungers axially when electrically energized. A gap is defined between the plungers so that the first plunger is slidable between one tube end and the second plunger and the second plunger is slidable between the other tube end and the first plunger. The first plunger closes one port when moved thereagainst and has a peripheral flow path permitting flow when moved away. The second plunger closes the other port when moved thereagainst and has an outer peripheral flow path and a communicating inner axial flow path permitting flow when moved away. The plungers when moved together close the second plunger axial flow path.

Abstract: A container for holding fluids in isolation includes an outer container and two deformable inner containers carried within the internal space of the outer container. The outer container is provided with a view port enabling the user to visually examine the inner containers. The inner containers have respective ports communicating with their interiors. As fluid is withdrawn from the first inner container its volume is reduced so that the second container may receive a like amount of fluid. The second inner container may hold colorants or absorbents. The container may be used with various chemical applications, such as high performance liquid chromatography or fluid injection analysis, wherein supply fluid is withdrawn from the first inner container, used, and returned as waste fluid to the second inner container so that the overall volume of fluids remains relatively constant.

Abstract: The disclosed HPLC flow schematic back-flushes the guard column with mobile phase once every operating cycle, the regular cleaning maintaining its effectiveness and useful life. This mobile phase flow reversal is accomplished by imposing a two position multiple port switching valve between the guard and separation columns. In one valve position, the mobile phase is pumped in one flow direction through both the separation and guard columns, but the switched valve maintains the same flow direction only through the separation column and reverses the mobile phase flow direction through the guard column, for effectively cleaning the guard column. Moreover, the mobile phase back flow is directed over the emptied sample drawing needle for cleaning it to reduce possible sample cross contamination. The improved flow circuits use basically only the typical HPLC system components, except for some insignificant modifications from existing injector designs.

Abstract: The disclosed HPLC column is formed with overlying concentric inner and outer tubes. The flow path is established via the inner tube bore that holds packed absorbent, end filters and capping sealing members, and end coupling members cooperate with the inner tube at its ends. The sealing and end coupling members have conventional configurations for establishing a sealed connection with capillary lines and their fittings, for the series flow testing use through the column. The inventive method and manner of assembly provides that the outer tube overlies all of the inner tube and both sealing members, but only part of each end coupling member. The ends of the outer tube are then deformed radially inward to become mechanically interlocked with the end coupling members, as the column, holding also the filters and sealing members within the inner tube.