Multi-analytical Approach To The Study Of Pigments And Binding Media In Precious Ancient Polychrome Cultural Relics

Chinese culture has a long history standing and remains a large number of elegant and precious polychromic cultural relics, including mural paintings in caves and tombs, colored drawings on ancient architectural heritages and ceramic paintings. These cultural relics possess not only cultural and artistic value as well as the important material evidence of the ancient civilization and the course of history research, artifacts, in addition to cultural and artistic value, but also study and explore the process of history, the ancient civilization material evidence. Studying the pigments, binders and other raw materials in polychrome relics is the foundation to study its ancient technology and has an important guiding significance of reinforce and protection.However, there are only few systematic studies about the pigment and binder identification as well as ancient technology research. In this article, an integrated analytical method was put forward based on consulting a large amount of literatures. Firstly, micro-destructive sampling and cross-section analysis were used to study the stratigraphic sequence of layers. As for the identification of pigments, the database about the element compositions and characteristic peaks in Raman spectra of pigments was established. Based on this, the method to identify pigments was put forward in which epoxy resin was used to embed the samples of polychrome relics, cured at room temperature and polished to expose the cross-sections, and then ordinary optical microscope was applied to observe the profile of the sample structure, back scattered electron (BSE) image and energy dispersive spectrometer (EDS) were utilized to analyze the element composition, Raman spectroscopy (RS) was used to get the structure information. The method to determine organic binders was also proposed in which several cross-section slices were made at the beginning of the experiment, staining technique was applied to declare the distribution of oil and protein, immunoassay was employed to identify egg white and mammalian animal glue. These methods were applied to detect pigments and binders in samples from mural and clay structure paintings from Maiji Mountain Grottoes as well as colored drawings from the Yanxi Hall in the Palace Museum. The results indicate that cross-section method shows the profile clearly. Pigment identification by EDS and RS, which give the information of element compositions and substance structure, have a high reliability. Binder identification by staining technique and immunoassay shows the binder distribution clearly. These integrated method is an intensive and exhaustive method to indicate the inorganic and organic ingredients in polychrome samples. Most importantly, it is easy to operate and cost efficient.Immunoassay, such as enzyme-linked immune sorbent assay (ELISA), immunofluorescence microscopy (IFM) and chemiluminescence immunoassay, has advantages of lowtestingcost, easy operation, high specificity and sensitivity. However, this method was limited in detecting proteinaceous binders, including egg white, egg yolk, collagen type I, etc. and does not cover the identification of binders derived from plants, such as Chinese lacquer, peach gum, rosin, etc. In this article, immunoassay to identify peach gum is studied. Glycoprotein was extracted and purifiedfrom peach gum before used to immune rabbits and the antibody got through titer test and specificity before used to test peach gum.