Chromatography Forum

Hi All,

I have a strange issue. I make sugars analisys with Dionex ICS 6000. Issue is that I have carry over but not always. For exampel I start with 3x standard than I have blank and than next blank. With first blank I donst see any carryover but if I inject second blank sometimse I see my standards peaks.

What can make suche a strange issue? I wash syringe, loop and all system after every injection with height volume wash solvent.

Thanks for help.

M

I've had that happen occasionally with anions. I just assume something got hung up somewhere. It hasn't been enough of an issue to worry about for me since it doesn't happen often. Is your second blank from the same cup? Sometimes I've seen a cup containing a blank get contaminated because a drop of liquid gets stuck to the sampling tip. That liquid then contaminates the blank when it takes it from the cup.

I used two different vials with blank. They are not polluted

Does your system have a guard column? Maybe something gets hung up there. I never tried removing the guard column to my system because the carryover is not a big problem.