The museum in a test tube - Adding a third dimension to the evaluation of the impact of volatile organic acids on paper

Collections of art on paper, libraries and archives in general, are striving for optimal storage conditions for cultural heritage in their deposits and exhibition facilities. Therefore, properly estimating the risk of volatile organic compounds emitted from historic and recent storage materials on paper-based collections is of utmost importance. Applying an optimized static headspace gas chromatography and mass spectrometry approach combined with cellulose-specific analysis provides insight into the potential degradation effects and mechanisms acting on two different paper samples (Whatman No.1 and historic rag paper) used as degradation indicators. Acetic and formic acid, two powerful volatile organic acids, were quantified with differing amounts, depending on the type of historic storage material tested. Molar mass and carbonyl group content were used to monitor cellulose degradation of the indicator papers. Combining these results in 3D plots helps to visualize synergies that evolve from mutual emission of acetic and formic acids. In addition, choosing between the two paper-based degradation indicators helps to evaluate different phenomena: Whatman No.1 reacts toward acid hydrolysis and is more sensitive, while rag paper helps to evaluate buffering phenomena as occurring in original materials.