Enhanced tobacco polyphenol electromigration and impact on membrane integrity

Previous work has shown the feasibility of removing polyphenols from tobacco extracts by electrodialysis using monopolar membranes. However, the low migration rates obtained for polyphenols were not sufficient to demonstrate that it was a practical technology. In the present work three anionic membranes of the same type, AM-4 or AM-2, were stacked in a cell and the duration of treatment was extended to 4 h. Trends previously observed during electromigration treatments for these membranes were confirmed. The AM-4 and AM-2 membranes gave final demineralization rates of 86.5 and 89.5%, respectively. High polyphenol migration rates were obtained with these membranes: for the AM-4 and AM-2 membranes the rates were, respectively, for chlorogenic acid 90.8 and 86.5%, for scopoletin 66.7 and 23.2%, and for rutin 81.3 and 31.1%. These results confirmed that ED has the potential for efficient separation of tobacco polyphenols. However, for both membranes, the mass balance showed a large (90%) decrease in nicotine in the treated tobacco extract, indicating a high level of nicotine electromigration. Measurements of the membrane characteristics before and after treatment were consistent with the AM-2 membrane becoming fouled during treatment.