Iron gall ink (IGI) is a historical ink made from a tannin, typically gallic acid extracted and hydrolyzed from gall nuts, plus iron sulfate, and water, as the principle ingredients. While recent research has identified the insoluble components of the ink, which are metal organic frameworks of composition Fe(C7O5H3)xH2O, this study explores the soluble components of the ink in addition to the precipitate. In particular, this study explores the role of pH and reactant ratios on the various products in IGI, as well as the identification of the soluble components. The precipitates were weighed and analyzed via IR and Raman spectroscopy, and the solutions were analyzed via UV-Vis, ESI, and UPLC. Results show that precipitates and soluble components are formed in different ratios depending on the pH and reagent ratios. The data also show that the soluble components have a different composition than the insoluble precipitates. The compositions, pH dependence, and spectroscopic data will be discussed.

Effects of pH and reactant molar ratio on iron gall ink products

254th National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.