Chromatography Forum

I am using a Shimadzu LC with a SIL-10AF auto sampler, for ethanol. I am currently experience an injection problem that I cannot figure out. The areas on my peaks are all very high, which is causing, obviously my concentrations to be too high. I have changed out the rotor, stator, needle and clipped tubing going into the needle. I also injected with my column disconnected 200ul of 70% methanol, to see if I had a plug that I just didn't find, I did this 12 times, then ran my mobile phase at the same volume, reconnected everything ran an injection of mobile phase and then my standard, that should be 12% ethanol, and it came up to 21%, does anyone have any suggestions what could be going on here?

I missed something here. After you disconnected, flushed, and reconnected everything, did you re-run the calibration? Also, just for completeness, what kind of column and mobile phase are you running, and was the retention time of ethanol consistent between when you ran your calibration and when you injected the check standard?

Found some plugging in a line that was apparently consistently moving until today! Thanks though