I am reading a journal paper in which separation of a plant extract was done on a C18 HPLC column using normal phase solvents of hexane:ethyl acetate, is this possible?
You can use it. But the mechanism probably will be different than classic RP.
regards
G
Maybe. Usually, the amount of water will retard the retention time of the molecular target. Ethyl Acetate may do the same thing but is less polar and may not be as effective.
Hexane- Ethyl Acetate is Non Polar solvent phase. There is a chance of solubility of bounded C18 in it. It is not recommended.
I don't agree with Ajay. C18 is an alkyl chain attached to silica gel - there is no risk about its solubility.
Regards
G
Hi. there, I am interested in the article you read. can you perhaps share the article with us
Thanks.
Ah, I see it would be called non-aqueous reverse phase and this can be done.
In all chromatographic process the separation is carried out due to the partition (affinity) of the components of a mixture between the stationary phase (octadecyl in this case) and the mobile phase (hexane-EtOAc). As far as I know, that combination (C18 column and hexane-ethyl acetate as eluent) could be used to separate non-polar o very low polarity compounds. But those types of compounds are analyzed much better using GC and GC-MS. The situation you mention is quite bizarre and could be (very probably) a error in the article because if Hexane-EtOAc is used as a solvent, most of the compounds normally found in plant extracts will not be retained (separated) in a C18 column and will elute with the solvent front.
In fact, ethyl acetate is used to clean and reconstitute C18 columns!
What is the paper you are referring to? What are the components separated?
At this point I agree with Narom Chamkasem: repeat the chromatographic run (with the same plant extract or similar) and see what happens.
A dissertation is not a revised manuscript and, considering that the chromatographic conditions it mentions are quite strange (a C18 column and hexane-ethyl acetate as the eluent for the separation of a plant extract), it could probably be an error. Why do not you ask the author of the dissertation directly? Diterpene mixtures are usually separated on a C18 column using a methanol-water mixture (gradient).
Whats logic using C18 stationary phase when you are using non polar mobile phase. Analyte may get eluted in void volume
- Badges
- Science topic