Column overloading.

[joelyue]

My chromatography method requires one of my columns to be overloaded.
i know that column overloading is not recommended but what are the side effects of overloading the column and how should i take care of the column to lengthen the lifespan of the column.

[Kimico]

Why do you need to overload it? Do you have to inject your sample neat so as to have more mass of the analyte in question on the column?

The peak itself for the molecule in excess will more than likely exhibit symmetry problems (peak fronting).
1)Washing the column accordingly after done with analysis can help prevent permanent changes to the chemistry in the column. Depending on the nature of the sample you are injecting and the mode of chromatography being used, you can evaluate different solvents for cleaning your column(IPA, ACN, MEOH,THF, HEXANES).
2)Try using a column guard. However, if you are trying to save $$ by means of extending the life of the column this option would defeat the purpose.
3)Think of the column as a consumable (as Tom Jupille has written before).

I don't have much experience in LC but this is what I can think of. Hope it helps!

[Uwe Neue]

what do you mean by "requires the column to be overloaded"?

If you are doing something along the lines of preparative chromatography from a cruddy sample, you need to think about getting the crud out of the column again.

If you just inject too much of a clean sample, for example to get a measurable signal from small constituents of your sample (as in an impurity profile), then don't worry about it: your parent peak will be wider then it should be, but this does not do anything to your column.

If you inject a clean sample from a wrong (or too strong) solvent, all your peaks will get wider, but again, this does not do anything bad to the column.

Did I miss something?

[joelyue]

I have to overload the column because of the abundance of interference ions in my sample. My column detects F ions while the ions i am interested is Cl and my sample contains 25% F ions. And i cannot think of any other way to seperate the F and Cl, other than using a first chromatography column to carry out a partial seperation before injecting the partially seperated Cl peak into another chromatography column to quantify.

[Uwe Neue]

It would have helped if you would have said up front that you are doing anion analysis...

In principle, my comment #2 above applies: don't worry about it (assuming that you are not using a silica-based column for your ion analysis).