Chromatography Forum

If you are stuck with regular HPLC the best option will probably be to derivatise the oligomers with a UV / fluorescence label. 2-aminobenzamide and 2-aminopyridine are quite popular. The label improves separation on amino and amide phases, lets you use UV or fluorescence detection and also gradient elution. For columns, the tosoh Amide-80 is an excellent choice, also the new Amide phase for the UPLC from waters is very good if you have an ultra high pressure system. An alternative option would be to use graphitized cabon columns (Thermo are the only supplier of these types of analytical columns that I know of)

The best resolution you can get without labelling is probably via the Dionex PA series of columns. The PA1 can do virtually everything, although they normally recommend the PA100 or 200 for oligosaccharides. These columns run in a mobile phase of NaOH /NaOAc and normally detection is by pulsed amperometry so it means you need a special HPLC (e.g. Dionex ICS 5000, Metrohm and Antec also have competing instruments). May be worth considering if more of these oligosaccharides are going to be coming for analysis.

The best separation is indeed by anion exchange LC as sold by Dionex (their columns show superior separations). It is not necessary to have a dedicated HPLC system, we use an ordinary stainless steel system for more than a decade in combination with a pulsed amperometric detector (Dionex or Eg&G) and it works fine, provided you have installed a seal wash. You need a He degassing system to keep oxygen and carbondioxide out of your eluents.