Chromatography Forum

Need help, I am using Shimadzu GC 2010.
I have inject some sample that have high concentration, after that, if i just inject solvent only, previous peak that i got from high concentration sample injection still appear.
Someone know what is wrong with the instrument?

You may have done what is called a 'backflash' of the sample into cooler parts of the injector. Once deposited there, repeated injections of solvent may 'wash' them out onto the column and to the detector.

OR

You may have a lot of active sites in your injection port or on the column itself and deposited your analyte on them. Then additional injections of solvent may dislodge them and allow them to elute to the detector.

Knowledge of the appropriate injection liner, the amount of sample to be injected, and the speed of sample injection and evaporation are not always present among those teaching you how to do GC.

Of course there is the oldest error of all, not washing your syringe and having traces of the previous sample when you take up the next injection solution.

Good luck,

Rodney George

I'm not that old in the GC field, but I made the same thing with some PCB, which are very sticky. So, try to bake out your gc and the flush it with solvent. For me it took like a week to cleaned it out.