Chromatography Forum

Hi! I'm doing separations using a Shimadzu 17A GC, using a TC-1 column 0.25 mm i.d. x 30 m. I have been working with split ratios of 10:1, 5:1, 3:1, since my compounds are in very small concentrations. However, the problem is, recently the machine can't achieve such split ratios, I'm getting 100:1, 60:1, 30:1, too high for the samples I have, and I'm not getting any peaks. Does anybody have an idea of what's going on with the machine? Why I'm not being able to reach the split ratios I want?, even when I set the machine to 10:1, it quickly goes to 50:1 or higher.
Help please!

It sounds like a blocked flame tip or column.

best wishes,

Rod

I have done steam cleaning several times, and left the column overnight at 220 oC but the problem continues... Can it be something wrong with the machine, or do I need to change the column?

Hi Aquarius

For sure it can be someting wrong with the machine. Time for a service call.

Peter

It's irrelevent with your problem, but you're supposed to use splitless injection if you are looking for low conc. samples.

I called technical service and they checked the machine. All the problem was produced by a worn-out septum, unbelievable..
Well, it's working fine now , thanx for posting