Sample injection manner null for liquid chromatograph

摘要

PURPOSE:To exactly inject a sample into a column by connecting a sample loop between a pump and a column to the intermediate part of a suction pipe, introducing only the set volume of the sample into the sample loop and switching a valve to the original state in the case of injecting the sample liquid into the column by a variable volume injecting method. CONSTITUTION:The piston of a measuring syringe 20 is pulled to suck the sample liquid 18 via a gas into the suction pipe 14 connected to the syringe 20 while the 6-way valve is in the connected state of a solid line. The 6-way value is then switched to the dotted line connection to connect the sample loop 22 connected between the pump 28 and the column 30 to the intermediate part of the suction pipe 14. The piston of the syringe 20 is then pushed to introduce the sample liquid in the suction pipe 14 on the syringe 20 side by as much as the set volume into the loop 22. The 6-way valve is then switched to the original state to inject the sample liquid in the loop 22 to its column 30. The front end of the suction pipe 14 is held as an open end while the syringe 20 is held closed in this way and the sample liquid is injected by the exact volume into the column without being affected by the high pressure in the loop 22.