关键词: 石榴皮植物染料, 羊绒纤维, 安石榴苷, 鞣花酸, 染料鉴别, 植物染标准体系

Abstract: In recent years, the international community has paid close attention to global environmental issues, and the concept of sustainable development has gradually become the theme of social development. With the popularization of the concept of ecology, health and environmental protection, the application of natural dyes in textiles has been paid more and more attention. At present, plant dyes are one of the most important sources of natural dyes. A variety of plant dyes have been applied in textiles. Pomegranate peel, as a renewable resource, is one of the common plant dyes and has been widely used in the field of ecological textile dyeing. However, there is no corresponding identification method and standard for pomegranate peel plant dyes on the market. In order to improve the lack of plant dyeing standard system, it is necessary to establish the identification method and standard of pomegranate peel plant dyes.
In order to improve the lack of plant dyeing standard system and establish the identification method and standard of pomegranate peel plant dyes, this paper studies the identification of pomegranate peel plant dyes and their dyed cashmere fibers. Firstly, the pomegranate peel plant dyes were tested by ultraviolet spectrophotometer to determine the markers for identifying pomegranate peel plant dyes. Then, the standard substance, pomegranate peel plant dye and its dyed cashmere fiber extract were detected by ultraviolet spectrophotometer and liquid chromatography-mass spectrometry in negative ion mode. By comparing the retention time and mass spectrum of the dye, the dyed cashmere fiber extract and the standard substance, and combining with the characteristic peaks contained in its ultraviolet-visible absorption spectrum, a perfect identification standard system was established to identify whether the dye and cashmere fiber were pure pomegranate peel plant dye and its dyed cashmere fiber.
The experimental results show that punicalagin and ellagic acid can be used as markers to identify pomegranate peel plant dyes and their dyed cashmere fibers. The quasi-molecular ion peak m/z 300.9862 was detected in the mass spectrometry of pomegranate peel plant dyes, and the retention time was 1.02 min. The quasi-molecular ion peaks m/z 300.9896 and 300.9868 were detected in the mass spectrometry of direct dyeing and ferrous sulfate post-mordanting cashmere fiber extract, and the retention time was 1.02 min and 1.04 min, respectively. Both of them were similar to the peak time of ellagic acid standard at 1.02 min. In the range of ±2.5 % deviation allowed by the standard, combined with the fact that the UV-visible absorption spectrum only contained gallic acid at 277 nm and ellagic acid at 255 and 357 nm, it could be determined that the dye and its dyed cashmere fiber were pure pomegranate peel plant dyes.
At present, although a variety of identification methods and standards for plant dyes have been established, there is still a lack of standard systems for some plant dyes in the market, and consumers cannot verify the conformity of products from the standards. Therefore, in order to enable consumers to purchase satisfactory plant dye products, identifying the corresponding plant dyes and their dyed fabrics is still the top priority in the development of plant dyes.

Key words: vegetable dye for pomegranate peel, cashmere fiber, Punicalagin, gallogen, dyes identification, Standard system of plant dyeing