Chromatography Forum

Hi all,

This question is probably very simple for you. Sorry for that. I looked it up on the internet during a few hours but I was not able to find a proper answer.

In some journal articles, I can read "the split ratio is X:1" and in others "the split ratio is 1:X".

Split ratio = split vent flow rate / column flow rate

Fraction sample transferred = column flow rate / (column flow rate + split vent flow rate)

For instance, let's say that the column flow rate is 1 mL/min and that the split vent flow rate is 100 mL/min.
It means that the split ratio is 100:1 and that the fraction sample transferred to the column is 1/101. (please correct me if I am wrong)

So, what would a split ratio of 1:100 would mean ? Would it mean that 100/101 of the sample is transferred to the column ? Why not using splitless then, since it would result in almost the same chromatogram, right?

Or do authors who write split ratio of 1:100, actually mean 100:1 ? Are those notations the same, is one of them false, or do they mean different things ?

Split ratio of 1:X is not rare. For example, in an Agilent presentation, slide 11, it is mentioned that the minimum recommended for the split ratio varies from 1:2 to 1:75 depending on the column mm.

Thank you very much for your time !

So, what would a split ratio of 1:100 would mean ? Would it mean that 100/101 of the sample is transferred to the column ?

No. It means that 1/101 would get transferred to the column.

It's just a terminology thing - and you're just stumbling about putting on your underwear !!!

The two are usually interchangeable. Just as some people write a dilution factor 1:100 or 100:1 both mean taking 1 part and diluting to 100 parts.

Almost as confusing as Trichloroethene and Trichloroethylene