Rheodyne, LLC

Spectra-physics Gmbh

Stephen R Bakalyar

Ronald E Honganen

Reginald E Sylvester

An injector is described for injecting a sample at a high pressure into a chromatographic column, which avoids sample dilution that is characteristic of bypass loop injectors, and which also avoids significant flow interruption into the column that is characteristic of prior non-bypass injectors. The stator includes pump and column ports with openings (34a, 42a, FIG. 4) at the stator-rotor interface, where the openings are spaced by a small angle (m) of less than 10.degree. from one another. In the load position, a channel (50) formed in the interface surface of the rotor, which connects the pump and column openings in the load position, extends away from the pump opening by an angle (n) which is many times greater than the angle between the pump and column openings. As a result, as the injector is turned toward the inject position, the channel (50) continues to connect the pump and column openings until the rotor is close to the inject position. As the inject position is approached (FIG. 8), the trailing edge (50t) of the channel passes beyond the pump openings (34 a), while the leading edge (50f) of the channel connects to a sample opening (the channel is always connected to the column opening (42a). Thus, when the rotor is rapidly turned from load to inject positions, there is only a very brief interruption of liquid flow into the column.

Injector with minimal flow-interrupt transient

A sample injector is described for receiving a sample at atmospheric pressure and injecting it at a high pressure into a chromatographic column, which is convenient to use and which avoids loss of the sample. The device includes a rotor and stator with flat adjacent faces, and a passage in the rotor for receiving a syringe needle that can transfer the sample into an aligned port in the stator, wherein the needle-receiving passage extends parallel to the axis of rotation of the rotor but is offset therefrom. This enables the needle to be inserted with its tip flush with the interface between the rotor and stator, so that no sample lies in the rotor passage after operation of the syringe, and so that rotation of the rotor isolates the syringe needle from the high pressure ports. With this arrangement, and with the needle end ground perpendicular to its axis, all of the sample in the syringe is transferred to the stator port and from there to the column.

Sample injector

Apparatus and method for liquid chromatography applicable to systems employing more than one solvent for the carrier. The forming of bubbles in the pumping means employed is prevented by special pretreatment of at least one solvent of the carrier, the pretreatment involving sparging of the solvent with inert gas.

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Berkeley, CA, United States of America

Stephen R Bakalyar