Query about c18 column

[kshiprakapil]

Dear all the members

can I use chloroform:methanol:diethyl amine in ratio of 90:10:0.2 respectively as mobile phase in c18 column for hplc analysis. I need some papers where chloroform was used as mobile phase with c18 column.

thanx and with regards.
Kshipra Kapil

[Gerhard Kratz]

Before you can do your first injection, your C18 column is dead. No, you cannot use Chloroform in RP chromatography with 90% in the mobile phase.
Why you want to do that?

[HPLCaddict]

Before you can do your first injection, your C18 column is dead. No, you cannot use Chloroform in RP chromatography with 90% in the mobile phase.
Why you want to do that?

Ehm, really? I mean, I cannot think of a good reason why one wants to use Chloroform as eluent in RP-HPLC, but why should Chloroform kill the column?
As long as the 10% are not water it should work (in principal).

[tom jupille]

Dichloromethane is occasionally used to flush junk from reversed-phase columns, so I wouldn't expect chloroform to damage anything. Miscibility with previous aquous solvents would be more of a concern.

[rhaefe]

I don't have my copy in front of me but you might want to check out:
"The HPLC Solvent Guide" by Paul C. Sadek.
There is a chapter covering chlorinated alkanes and chlorinated benzenes.

rh

[Gerhard Kratz]

In RP water or aquous buffer is in mobile phase with minimum 3-5% or more. And with regards to the imiscibility of Chloroform and Water this is the problem what will kill the column packing. Following the HPLC Solvent Guide of Paul Sadek to rinse the column with different solvents and at the end with Chloroform will take very long time and at the end it is cheaper to buy a new column.

[HPLCaddict]

In RP water or aquous buffer is in mobile phase with minimum 3-5% or more. And with regards to the imiscibility of Chloroform and Water this is the problem what will kill the column packing. Following the HPLC Solvent Guide of Paul Sadek to rinse the column with different solvents and at the end with Chloroform will take very long time and at the end it is cheaper to buy a new column.

Of course you have to carefully exclude water when using chloroform, but having water in the mobile phase is not a necessary prerequisite for RP-HPLC. I've seen methods with nonaqueous eluents (this is sometimes coined "NARP" - nonaqueous reversed phase). The methods I've seen used gradients of methanol and acetonitrile or THF, though, no chlorinated solvents.
So, using dichloromethane/methanol (there is no immiscibility between those two, if I recall correctly) on C18 might be a possibility when you're dealing with extremely hydrophobic analytes - I'd prefer using a less hydrophobic stationary phase with the usual RP-eluents .

[HPLCaddict]

Just to shoot out a quick-Google-example: Separation of carotenes by NARP using dichloromethane/ACN on C18:
http://onlinelibrary.wiley.com/doi/10.1 ... 5/abstract