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- Posts: 9
- Joined: Wed Jun 13, 2007 4:31 pm
Hello,
I am separating oligomers obtained in the degradation of poloxamers. I use a PSS SDV 500A porosity column and chloroform as eluent.
I prepare two solutions of different dilutions from the same initial vial. They are both clear in the beginning. I inject the samples and from the more diluted one I get two peaks (2 MW fractions), while the more concentrated one gives only one peak (the low MW fraction). After a while I notice a suspension in the more diluted one, while the concentrated one stays transparent.
Do you have any idea what is going on? I guess it is a problem of different solubility of the different MW fractions, but I don't understand what is happening. If the high MW fraction precipitates when more chloroform is added, how come it appears in the diluted one (that becomes turbid) and not in the concentrated one? When I inject the initial solution the peak of the high MW fraction appears so it is not a problem of lack of solubility in the first dilution when compared to the second.
All the best.
I am separating oligomers obtained in the degradation of poloxamers. I use a PSS SDV 500A porosity column and chloroform as eluent.
I prepare two solutions of different dilutions from the same initial vial. They are both clear in the beginning. I inject the samples and from the more diluted one I get two peaks (2 MW fractions), while the more concentrated one gives only one peak (the low MW fraction). After a while I notice a suspension in the more diluted one, while the concentrated one stays transparent.
Do you have any idea what is going on? I guess it is a problem of different solubility of the different MW fractions, but I don't understand what is happening. If the high MW fraction precipitates when more chloroform is added, how come it appears in the diluted one (that becomes turbid) and not in the concentrated one? When I inject the initial solution the peak of the high MW fraction appears so it is not a problem of lack of solubility in the first dilution when compared to the second.
All the best.
