Analysis And Characterization Of The Binding Media Of Ancient Polychrome Artworks By MALDI-TOF-MS

Polychrome artworks are an important component of cultural heritage of human civilization. The analysis and characterization of binding media for ancient polychrome artworks is of great importance for conservation and restoration. In this thesis, MALDI-TOF-MS (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, MALDI-TOF-MS) was used for analysis and characterization of the binding media of polychrome artworks. The sample pretreatment and determination conditions were optimized. The model samples were respectively prepared by mixing the different pigment with egg or animal glue (hide glue, rabbit glue, bone glue). The proteinaceous binding media of the polychrome layers for Terracotta Army of Qin Shihuang was identified. The results proved that animal glue was used as the binding media in the polychromy Terracotta Army of Qin Shihuang.The dissertation consists of five chapters as follows:Chapter1:ReviewThe analytical methods for characterizing the binding media of ancient artworks were reviewed in detail, which include Microchemical tests, Spectroscopic techniques (UV-vis, Fluorescence, IR, Raman spectroscopy), NMR, Chromatographic techniques (GC、HPLC、 PY-GC-MS), Mass spectrometry and related techniques, and so on. The current trends in the identification and determination of binding media in polychromy are discussed for the research of conservation and restoration. The topic of the thesis was proposed based on the review.Chapter2:Experimental treatment methodsIntroduce the principle of MALDI-TOF-MS, the experimental materials and the experimental approach. Chapter3:Analysis and characterization egg proteins and its model samples by MALDI-TOF-MSMALDI-TOF-MS was be used for identification egg proteins in model samples. The determination conditions were optimized.0.1%TFA was selected to extract the protein with the ultrasonic baths from the model samples. The enzymatic hydrolysis was performed with5.0μl of10μg/ml trypsin in18h for egg model sample at ambient temperature. A dialysis method was used to eliminate impurities. The result showed that the peptide mass fingerprint was different because of the different pigment used in the model samples.Chapter4:Analysis and characterization of animal glue and its model samples by MALDI-TOF-MSThe animal glue was determined by MALDI-TOF-MS. The experiment conditions were optimized. The results showed that the better result was achieved by combining complexation of EDTA with dialysis to eliminate impurities. The ratio of mineral pigments and animal glue as binding media was investigated in the experiment. The "peptide mass fingerprint" is not much difference for different kinds of animal glue. The result showed that the MALDI-TOF-MS method can distinguish among classes of binding media, i.e. among egg, animal glue, etc.Chapter5:Analysis and characterization the binding media of Terracotta Warriors by MALDI-TOF-MSThe aging effect was investigated for the model samples in the experiment. The content change of protein in the model samples was determined with UV-Vis spectrophotometry. MALDI-TOF-MS method was successfully applied to identification of the binding media of polychrome layers for Qin Shihuang’s Terracotta Warriors. The result reveals that animal glue is used as the binding media of the polychromy Terracotta Army for Qin Shihuang. It has shown that animal glue used as binding media has a long history in China.