[Jamemeup2152c]

Carbohydrates having less intense on UV absorption. Will these give peaks on HPLC with UV-Visible detector?

[enahs]

If they have absorbance in the UV region then yes they will. If it is not a very strong signal though, it will just lower your detection limit. Determine the maximum absorbance wavelength with a spectrophotometer. Also, determine the maximum absorbance wavelength in the mobile phase.

Also, try two different mobile phases, one buffered with a pH of 2 units above the pKa of any acidic hydrogens, and one buffered with a pH of 2 units below (if these are also in safe operating conditions of your column). I.E., optimize the absorbance for your compounds by either removing all the acidic hydrogen's or having them all there.

[JGK]

Is UV your only option? If not Refractive index (RI) or evaporative light scattering (ELSD) may give better results.

[Jamemeup2152c]

Thank you. Now I am doing derivatization of carbohydrates with Phenyl methyl pyrazolone (PMP). I did derivatization with some carbohydrates (ex: Glu,Man, Arab, etc.,).  But I am getting all the carbohydrate peaks at the same retention time. I am using C-18 column with H2O (100 mM amm.acetate buffer pH 5.5) : MeCN = 78% : 22%,  flow-0.8 ml/min.  What can I do?

[mahesh]

Some journals do report the analysis of sugars and corresponding acids on UV detectors (you might want to see a few papers on glucose oxidation) .. however, UV is not the best detector for carbohydrates. RI is a much better option. I could get much better detection and quantification of sugars on RID.