Development of Analysis Strategy
The development of a strategy for the analysis of organic dyes on yarns and organic pigments in paint requires consideration of the following parameters: level of destructiveness to both the object and the sample, diagnostic value, sensitivity, and reproducibility.
Liquid Chromatography-Photodiode Array-Mass Spectrometry is routinely used for analysis of organic dyes and pigments present in artifacts produced in Europe and the Americas. Its use in an Asian or, more specifically, Chinese context cannot necessarily be extrapolated because the majority of biological sources identified in Chinese artifacts were different from those found in the European and American artifacts. Liquid Chromatography-Photodiode Array-Mass Spectrometry however, will remain the core analytical technique because of its high diagnostic value, sensitivity, and reproducibility. The method used by the GCI will be optimized for the analysis of Asian organic dyestuffs and pigments. It will result in:
- a library of Ultraviolet-Visual (UV-Vis) spectra for color-contributing components and,
- an Electro-Spray Ionization—Negative Ion Mode (ESI-NIM) mass spectra database of the same diagnostic components of organic colorants including both MS and MS-MS spectra.
Additional techniques will also be investigated for their ability to identify important information not detected through Liquid Chromatography-Photodiode Array-Mass Spectrometry and for their ability to be less destructive on the object and sample. The project will consider the following additional analytical techniques:
- In-situ UV inducefluorescence illumination,
- Fourier Transform Infrared spectroscopy,
- Gas Chromatography-Mass Spectroscopy of carbohydrates to explore a possible link between sugars detected in a paint layer and the presence of organic pigments,
- Raman spectroscopy,
- Direct Temperature-resolved Mass Spectrometry,
- 3D-UV-Vis Fluorescence spectroscopy.
Page updated: January 2011