What is the best systematic approach to purify a UV silent molecule?

2 posts / 0 new
Last post
antibiotics's picture
What is the best systematic approach to purify a UV silent molecule?

Hi folks,

         By LCMS, I recently found a molecule from the tissue extract. I am thinking to purify this molecules for further characterizaton. The problem is , this molecule doesn't have any UV absorption. So I wonder what is the common approach to isolate these spectroscopy silent molecules. I currently don't have access to refractive index detector. Given the low abundance of this molecule, I doubt a RID can really help. Derivatization may be another approach, MS2 suggests this molecule may contain hydroxyle group. Any other ideas?


Dr. Analytical
Dr. Analytical's picture
The respose for refractive

The respose for refractive index is not dependent on absorbance, so it may give a good response (or at least better than the absorbance detector).  However, if all you want to do is purify this compound, and if the retention time is stable, you can make repeated injections and simply collect the outlet from the colum before it goes into the MS.  This will require many injections on an analytical column.  However, you can experiment with larger injected concentrations and/or injection volumes, and as long as you know the retention time window, and it is separated from other peaks, then this approach should work.  Having a fraction collector and autosampler would make this much easier.

There really are not any other easy options.  Buying a larger column would be the only other option.