Chromatography Forum

Hello everyone.
First of all, I apologize for my English, it is not my first language.

I am making liposomes encapsulating hydrophobic compounds. I am going to analize them in HPLC-UV. Since it is very difficult to separate the hydrophobic compounds from the matrix (in this case, phospholipids), we are going to inject them as a whole thing and then clean the column. Phospholipids are reported to be veeery contaminant to C18 reverse columns because of their high affinity to this phase. So I want to be sure that I have a good cleaning procedure in order to preserve my column and also for guarantee that my retention times don't change a lot between analysis.
I have found that I can clean my column with a step process in this way:

1. 100% metOH compatible with mobil phase.
2. 100% acetonitrile
3. 75:25 Acetonitrile:IPA
4. 100% IPA
5. 100% methylene chloride
6. 100% hexane

What do you think?
Also I am not sure if phospholipids are ion-pairing agents, and this is important because if they really are I guess I have to choose another method.
Thanks a lot!

PD: how do you analyse liposomes?

I would highly recommend to use SPE solid phase extraction as a first cleaning step BEFORE you inject your samples on an analytical column.

Hello Gerhard, thanks for your answer.
We wanted to use SPE or SLE but we don't know if our sustances may be also retained with the phospholipids. Because this is a very first assay, we don't want to put lots of efforts in making complicated analytical process and recovery analysis. But thanks, I am going to look up that option.