Characterizing organic colorants in mock-ups of a 15th-century iranian timurid qur'an by direct analysis in real time time-of-flight mass spectrometry.

摘要

The Detroit Institute of Art (DIA) has in its possession a 15th century Iranian Timurid Qur'an (accession number 30.323) as the centerpiece of the Islamic Art Collection. The Qur'an manuscript pages are folio size, highly polished, and brightly colored. The pages are composed of 10 distinct colors within sections of 15 pages and have inked calligraphy text written on them. The DIA is currently undertaking a multidisciplinary study on the Timurid Qur'an including the identification of the pigments, inks, binders, and paper sizing used in its construction. The instrumental analysis performed by the DIA showed the following results on the manuscript. X-ray fluorescence yielded only lead on the manuscript pages, indicating that colors were not derived from mineral pigments but organic ones. Raman spectroscopy was able to determine that the dark blue pages possibly contain indigo and the red pages madder, but too much fluorescence obscured the definitive presence of any pigments or dyes. The work here describes developing a new method utilizing direct analysis in real-time time-of-flight mass spectrometry (DART-MS) to identify the organic colorants in complex mixtures that are expected to be present in the manuscript pages from the DIA. Mock-up samples were made using different combinations of pigments, dyes, binders, and sizing materials that would have been used in the region and time period of the Qur'an. The spectra from the mock-up samples were used to generate a library for future comparison of the actual Qur'an samples. Utilizing mock-up samples aided in minimizing the destructive nature of the analysis and in investigating alternative methods of sample introduction.