KOPTRI provides GPC service with DMF (N,N-Dimethylformamide).

If the polymer does not dissolve in THF, amide solvent with higher solubility such as DMF (or DMAc, NMP) is utilized. When using DMF, salts such as LiBr, and LiCl are added to the solvent. The ions in the salt will disentangle the polymer chains, allowing polymers to elute well through the column pores. If LiBr is not added, the polymers would be eluted as in entangled form, which causes the GPC result to be higher than the actual (unreliable result), and thus it requires an extra caution. For DMP-GPC, selecting appropriate column and suitable standard must be discreet. Typical packing material of GPC column is crosslinked polystyrene, (divinylbenzene polymer: DVB) and these polymers swell up when they meet solvents with high solubility such as DMF. When polystyrene standards permeate through these DVB-columns, the standard will be absorbed to the column pores due to the similarity in the chemical structures, and it will cause polystyrene standards to elute slower than usual. It is sensible to use PMMA or PEG/PEO based standards instead of polystyrene in these cases. However, if we use GPC column that is not packed with DVB like Tosoh Corporation’s superAWM column or alpha column, it is possible to use polystyrene standards without absorptions. There are many commercialized columns for DMF, making it critical to know the packing material of these columns and select standards accordingly. If you need help with analysis, please send us a request by submitting ‘Application Form’ under ‘Contact Us’ tab, and supervising researcher will aid you with a punctual and meticulous reply.