Zhang X, Laursen R A
Department of Chemistry, Boston University, Boston, Massachusetts 02215, USA.
Anal Chem. 2005 Apr 1;77(7):2022-5. doi: 10.1021/ac048380k.
Analysis of dyes extracted from textiles of historical interest can give valuable information as to where, when, and how the textiles were made. The most widely used method for extraction of colorants involves heating with HCl, which frequently decomposes glycosidic dye components to their parent aglycons, with consequent loss of information about the source of the dye. This is particularly true for flavonoid dyes, many of which are glycosides. We have developed or improved upon two mild textile extraction methods that use ethylenediaminetetraacetic acid (EDTA) and formic acid and are efficient in extracting dyes, but preserve glycosidic linkages. The relative efficiencies of the HCl, EDTA, and formic acid extraction methods are compared by analyzing extracts of dyed samples of silk using HPLC coupled with diode array and mass spectrometric detection. HPLC profiles of EDTA or formic acid extracts of silk dyed, for example, with pagoda tree buds and onionskins are clearly distinguishable as to the plant material used, whereas profiles of HCl extracts are not. Thus, extraction of textiles with EDTA or formic acid reagents can yield significantly more information about the original dyestuff than can extraction with a strong acid.
对具有历史价值的纺织品中提取的染料进行分析，可以提供有关这些纺织品的产地、年代和制作方法的宝贵信息。最广泛使用的提取着色剂的方法是用盐酸加热，这常常会使糖苷类染料成分分解为其母体苷元，从而失去有关染料来源的信息。对于黄酮类染料来说尤其如此，其中许多都是糖苷。我们已经开发或改进了两种温和的纺织品提取方法，它们使用乙二胺四乙酸（EDTA）和甲酸，能够有效地提取染料，但能保留糖苷键。通过使用高效液相色谱（HPLC）结合二极管阵列和质谱检测来分析丝绸染色样品的提取物，比较了盐酸、EDTA和甲酸提取方法的相对效率。例如，用槐树芽和洋葱皮染色的丝绸的EDTA或甲酸提取物的HPLC图谱，根据所用植物材料的不同有明显区别，而盐酸提取物的图谱则没有。因此，与用强酸提取相比，用EDTA或甲酸试剂提取纺织品可以获得关于原始染料的更多信息。
