Exploring the potential of pyrolysis-comprehensive two-dimensional gas chromatography/mass spectrometry in the characterization of Chinese inks of ancient manuscripts

Despite the historical richness of ancient records mentioning or describing Chinese ink since the first centuries CE, the manufacture and use of Chinese inks in early history remain obscure. The characterization of inks from dated ancient manuscripts could not only give us new information on the evolution of the manufacture of inks but also on their use. The purpose of this work was to optimize and then validate a Pyrolysis-comprehensive two-dimensional gas chromatography/mass spectrometry (Py-GCxGC/MS) approach to identify compounds characteristic of ingredients used in the manufacture of traditional Chinese inksticks. Performance assessment was accomplished by studying the distribution of compounds characteristic of soot and proteinaceous binder and by performing repeatability tests remaining constant from one analysis to the other. A strategic sampling protocol and the optimized Py-GCxGC/MS method was then applied for the first time to characterize ancient inks manufactures from tiny fragments of Tocharian manuscripts (6th −8th centuries CE) of the Pelliot Collection stored in the Bibliothèque nationale de France as part of the “History of the Tocharian Texts of the Pelliot Collection” (HisTochText) ERC project. The approach allowed us to distinguish compounds attributable to the ink present from those imputable to the paper support and its preparation. Compounds characteristic of soot as well as of proteinaceous material were identified. Moreover, our data provides conclusive evidence for the use of a wide range of additives in the manufacture of inks. Based on the analytical data, this work demonstrates the potential of a Py-GCxGC/MS approach in the characterization of inks from tiny fragments of ancient manuscripts of historical value, making this approach highly relevant to the study of inks manufacture.