An aqueous solution of unknown concentration of Polyethylene Glycol (PEG) is prepared. After UV-spectroscopy,to investigate the conc., results were found inconsistent. Any better technique or suggestions? Thanks
You can try to run analytical HPLC to detect the PEG. The issue is that PEG by itself will only absorb strongly at wavelengths < 200nm (well into the UV range), so you may need to conjugate the PEG with a molecule that absorbs strongly in the range you are looking at.
@David: Thank you. I have actually tried UV but its not working somehow since at some concentrations, it fails to detect it with pop windows showing message such as "invalid absorbance" or invalid range".