Methods for Injecting Samples in Liquid Chromatography, Particularly in High Performance Liquid Chromatography

Abstract

A sample injection method for liquid chromatography is performed with an injection valve having a waste port, two sample loop ports, and two high-pressure ports. One high-pressure port can be connected to a pump and the other high-pressure port can be connected to a chromatography column. A sample loop is connected to one of the sample loop ports on one end and to a pump volume of a sample conveying device on the other end. A section of the sample loop can be separated to facilitate receiving a sample fluid in the sample loop. A control unit controls the injection valve and the sample conveying device. The sample injector allows a sample to be loaded into the sample loop and then pressurized to an operating pressure prior to injecting the sample into the chromatography column. The sample loop may also be isolated from the operating pressure for facilitating depressurization of the loop.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]Applicant claims the benefit, under 35 U.S.C. §120, of U.S. patent application Ser. No. 12 / 863,976 filed Jul. 21, 2010, and entitled “Sample Injector for Liquid Chromatography, Particularly for High Performance Liquid Chromatography.” The entire content of this prior patent application is incorporated herein by this reference.TECHNICAL FIELD OF THE INVENTION[0002]The invention pertains to methods for injecting samples for liquid chromatography, particularly for high performance liquid chromatography (HPLC). The sample injection process provides for pressure compensation during a sample injection sequence, or during a post sample injection sequence, or during both sequences.BACKGROUND OF THE INVENTION[0003]In HPLC, a sample to be examined needs to be injected into a high-pressure fluid flow, wherein this flow can be interrupted only as briefly as possible. For this purpose, high-pressure injection valves are used that allow a nearly uninter...

AI Technical Summary

Benefits of technology

This approach extends the service life of high-pressure valve components by minimizing wear and preventing pressure-related damage, ensuring uninterrupted fluid flow and maintaining system efficiency without the need for additional flushing, thus reducing operational costs.

Problems solved by technology

Furthermore, WO 2006 / 083776 discloses a sample injector for preventing pressure surges that occur during the actuation of the high-pressure valve and could negatively affect the efficiency and the service life of the chromatography column.

According to non-previously-published German Patent Application DE 10 2007 059 651 A1 of the applicant of Dec. 10, 2007, which pertains to a sample injector for high performance liquid chromatography and features a high-pressure change-over valve with optimized service life, these flows cause damage to the high-pressure valve components.

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