Dear Sir. Concerning your issue about the separation and quantification of galactose and 3,6-anhydrogalactose using HPLC with a Aminex HPX-87P or ZORBAX-C18 column, and RI detector. You can separate and quantify galactose by using Aminex HPX-87H ion-exchange column (300 × 7.8 mm), RI UV 210 nm, a3 mM H2SO4; b0.7 mL/min isocratically; c65 °C; d20 μL according to Garde and others (2012). For more details, I think the following below links may help you in your analysis:

http://onlinelibrary.wiley.com/doi/10.1111/1541-4337.12148/full

http://www.bio-rad.com/webroot/web/pdf/lsr/literature/Bulletin_6333.pdf

https://ainfo.cnptia.embrapa.br/digital/bitstream/item/42684/1/sugars-and-fatty-acids.pdf

Thanks

Hi Teklebrahan! There is very little you can optimize using the Aminex column, so I think you will not be able to separate the two sugars with this method. I would expect also the same for the C18 column - It depends a bit what you ultimately want to do with your samples, but if you have a UV detector on your HPLC system I would try to label the reducing end with DMB (1,2-diamino-4,5-methylenedioxybenzene). It can be done fairly simple and in a robust manner - you can find further information here: doi: 10.1016/j.ab.2011.07.005. Good luck!

In theory you can separate based on their sidegroups but I have no idea on the selectivity of the HPLC column or the mobile phase that can achieve this.