Chromatography Forum

I’m trying to dissolve butylbenzene in 50/50 water/ACN. The problem is that it is immiscible in 50/50 when you add it directly. I tried to dissolve first 0.5 ml in 10 ml ACN, so far no problem. Than I want to add the water (10 ml) but I get phase separation.
I tried heating, but didn’t worked well.
I’m afraid when I use contents like 80% or 90% ACN that the solvent also will act as a mobile phase. The retention time for butyl benzene will not be accurate.
Does someone have suggestions?

I'd just dissolve the butylbenzene in the ACN. Just keep the injection volume low (e.g. 5ul) when using high-organic as sample or standard solvent, and you should have no issues.

What I'm doing at the moment.....
Dissolve a high amount of butylbenzene in a large volume ACN. Add the water and then heat the solution. The ACN will evaporate first.
It is not very analytical but...

Guy, your solution sounds logical.

Can someone confirm his approach

consider it confirmed.

You could also add a small amount of the ACN solution to a water-acn mix but it would be better to inject a small amount in acn.

You could also saturate the Butyl benzene in water. I do not know the solubility but it could be looked up.