Hi,
Has anyone had an experience in adjusting the pH of sulfate containing polysaccharides? When I adjust the pH of carrageenan and dextran sulfate I found that the pH would change over time. For example, 0.5% kappa carrageenan has a starting pH of 8.3. I adjust its pH to 6.8 with
0.1 N HCl but after I let it stir the pH will go back up again. It takes several hours and the same situation happens. The pH will go down but after stirring for half an hour the pH will go back up. The carrageenan solution was hydrated for 4 hours and boiled for 3 min before cooled down to room temperature.My questions are whether this is normal properties of this kind of polymer and what is the best way to adjust the pH?
Thank you very much for any suggestion or recommendation.