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

摘要

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.

主权项

1. A method of operating a liquid chromatography system, the method including:
(a) isolating a sample loop of the liquid chromatography system from a high-pressure loop of the liquid chromatography system; (b) performing a pressure compensation operation including one of (i) when isolating the sample loop from the high-pressure loop leaves the sample loop at essentially an operating pressure of a liquid chromatography column, increasing a volume connected in the sample loop to reduce the pressure in the sample loop to essentially ambient pressure, or (ii) when the isolated sample loop is at essentially ambient pressure preparatory to injecting a sample liquid into the high-pressure loop, decreasing the volume connected in the sample loop to increase the pressure in the sample loop to essentially the operating pressure of the liquid chromatography column; and (c) when the pressure compensation operation comprises decreasing the volume connected in the sample loop to increase the pressure in the sample loop to essentially the operating pressure of the liquid chromatography column, further including connecting the sample loop to the high-pressure loop so that a pump pressure from a high-pressure pump of the liquid chromatography system is applied to the sample loop and a sample liquid in the sample loop is free to flow from the sample loop through a portion of the high-pressure loop to the chromatography column.