I am running a FID on a 5890. I run a splitless injection. I recently started injecting samples on my rear injection port. When I switched, my solvent peak started tailing dramatically. I cleaned out the injection port, replaced the injector seal and o-ring, put in a new liner and (multiple) new septa, a new column, and a new needle. The tailing is not quite a broad, but still eats up my GRO. The other problem with the tailing is that it varies. Sometimes it will be wide, sometimes it will not. It seems to be random. I have checked all of my flows and they are where they should be. The retention times for my DRO and surrogate are perfect every time. Any help will be appreciated.
Thanks.

Try cuting 10/20 cm of the column and see of the solvent peak is different....
Or try to reinstall your column...

Poor installation in the inlet,column contamination,graphites ferrules traces gives broad solvent peak...

hi
can you tell me what kind of column do you use please tell me the type of it and some operating codition?