Dear Saheli, I've been working with EPS for the last couple of months and according to the literature the best method to characterize EPS is to use NMR (Please see i.e. ''Comparison of growth characteristics and exopolysaccharide
formation of two lactic acid bacteria strains, Pediococcus damnosus
2.6 and Lactobacillus brevis G-77, in an oat-based, nondairy medium''). Then to determine it's composition you need to hydrolize your samples (3M HCl/ 3h/ 100C) and you can use HPLC to determine the content of each monosaccharide. If you want to determine molecular mass it is recommnded to go for size exclusion chromatography. There two very good specialist in that field: Luc De Vuyst and Juta Cerning. I found a lot of useful infromation in their papers. I hope that this helps.
Characterization of extracellular polymeric substances (EPS) has been performed using a column with higher separation range with LC-OCD-OND) for further characterization of the biopolymer fraction. For details consult https://www.ncbi.nlm.nih.gov