Method and device for on-column injection of a liquid sample into small diameter columns

摘要

A liquid sample 20 in a syringe 22 can be injected into a capillary column 30 with inner diameter less than 200 microns without inserting the injection needle of the syringe into the column. The end of a modified injection needle 25 according to this invention has a tubular opening with inner diameter sufficiently large so that the intake end 32 of the column can be inserted inside, thereby establishing an annular duct 35 between the needle and the column. A carrier gas is caused to flow through this duct while the plunger 24 on the syringe is pressed to squeeze the liquid into the needle, thus forcing the liquid into the capillary column 30.