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?