Chromatography Forum

Has anybody encountered an issue with the split ratio wondering on some methods?

Yes.

Welcome to the forum.

Peter

You dont have any theories as to the cause, it seems almost random, I'm the only operator so I know its not another human?

Hi chricol

If you stick around you will find that useful answers come more quickly if you put some details into your questions, so that other people have a clear idea what it is that you need to know.

The potential causes for fluctuating split ratios include poor gas mixing in the inlet (particularly relevant when doing headspace injections), inappropriate choice of inlet liner and packing, inconsistent injection volume, poor choice of solvent, instrument malfunction, particular combinations of solvent, inlet temperature and oven temperature ..... the list goes on.

So what was your question again ?

Peter

Thank You Your right my enquiry is kinda sketchy, the issue can be best described as for a given method on EZ chrom using a varian 3800 GC the method can be saved with a 30 split ratio lets say and week later,or so, when running a sample the result would be wacky and upon investigation the split ratio will have change to perhaps 10. This happens on 2 different varian 3800 controlled by 2 different computers.

Does this:

"The potential causes for fluctuating split ratios include poor gas mixing in the inlet (particularly relevant when doing headspace injections), inappropriate choice of inlet liner and packing, inconsistent injection volume, poor choice of solvent, instrument malfunction, particular combinations of solvent, inlet temperature and oven temperature ..... the list goes on."

provide any clues as to what might be going wrong ?

And does this;

Thank You Your right my enquiry is kinda sketchy, the issue can be best described as for a given method on EZ chrom using a varian 3800 GC the method can be saved with a 30 split ratio lets say and week later,or so, when running a sample the result would be wacky and upon investigation the split ratio will have change to perhaps 10. This happens on 2 different varian 3800 controlled by 2 different computers.

provide any information relevant to any of those potential causes of trouble ?

"The more you don't tell us, the more we can't help you."

I have a specific question; how do you know that the split ratio has changed ? And I still need to know the details of the operating conditions.

Peter