Hi, I would appreciate your help. I am running high pressure liquid hydrocarbons on a GC. Our samples are at 13000kpa so we attach our sample cylinder containing the liquid hydrocarbons to the gc. I am having issues with hydrocarbons remaining in the line I believe as I find it impossible to get a clean blank after a run in fact the blank looks like the sample chromatogram. Has anybody experienced this before? and what did you do to clean your lines? I purge the line with helium but it doesn't seem to do much. I wash/purge the line with pentane and this appears to clean it after a number of runs but I get a large pentane peak in the chromatogram. I need a quick effective method to clean the lines