关键词: 古代纺织品, 染料提取, 染料鉴定, 无损, 非侵入性

Abstract: The effective identification of dyes in ancient textiles can provide the best scheme for the preservation and restoration of related textile cultural relics, and important reference for the application of natural dyes and the development of new dyes and dyeing processes. Studies related to dye identification for ancient textiles are reviewed, with focuses on on the two aspects of extraction methods and detection techniques of dyes. Suggestions and development direction are provided for the effective identification of ancient textile dyes. 
The main extraction methods of dyes include solution extraction, in situ non-extraction, the adsorption technique by contact gel, etc. Both the solution extraction and in situ non-extraction methods have different degrees of invasive or destructive sampling of textiles. By contrast, the adsorption technique by contact gel does not require destructive sampling or special treatment of the sample, and the dye can be extracted by directly contacting the surface of the sample with the special gel for a certain time. Therefore, this method can achieve non-invasive and non-destructive sampling to a certain extent, which is a potential method for extracting dyes from ancient textiles.
Dye detection techniques mainly include spectrology, chromatography, mass spectrometry, and so on. According to the degree of damage to textiles, they can be divided into two main categories: non-invasive techniques and micro-invasive techniques. Non-invasive techniques can be used to detect a sample without damaging it (or slightly damaging it), such as UV-visible diffuse reflectance spectroscopy (fiber optic reflectance spectroscopy, FORS), fluorescence spectrum analysis, conventional Raman spectroscopy technology, and direct mass spectrometry technology. At present, most non-invasive techniques can obtain relatively effective detection results, but most of them have certain limitations. These methods often fail to obtain detailed information about the composition of dyes, which makes it difficult to analyze the composition and determine the source of dyes. Therefore, in most cases, current non-invasive detection techniques are only used for preliminary identification of dyes in ancient textiles. Microinvasive techniques require taking a small sample, or extracting the dye components from it, to make a sample ready for testing, such as surface enhanced Raman spectroscopy (SERS) and liquid chromatography-mass spectrometry (LC-MS). Due to the complexity of surface composition and aging condition of ancient textiles, at present, high performance liquid chromatography-mass spectrometry (HPLC-MS), which requires micro-invasive sampling, is still the most accurate, stable, and reliable detection technique. 
Finally, it is pointed out that the dye identification technology of ancient textiles is developing towards non-destructive, rapid and high precision, and developing effective noninvasive methods of sampling, building abundant spectrum database of dye, and developing new nondestructive testing technologies are key research directions in the future. 

Key words: ancient textiles, dye extraction, dye identification, non-destructive, non-invasive