Analysis And Identification Of Several Common Natural Botanical Dyes In Ancient China

Dyestuff is an important part of textiles.It not only makes textiles colorful,but also beautifies human life.These natural dyes obtained from animals,plants and minerals often change in color due to various factors during burial.In order to restore the original color of these precious textile relics,it is necessary to analyze and identify the dyestuffs used and understand the changes in the aging process.According to the dyeing methods recorded in ancient literature,eight kinds of traditional plant dyestuffs-Rubia cordifolia L.,Logwood,Safflower,Turmeric,Gardenia jasminoides,Sophora Japonica,Phellodendron Amurense,Lithospermum erythrorhizon Sieb.et Zucc.-were selected to dye pure silk and pure cotton cloth,and ultraviolet light was used to aging all the textiles dyed in the simulation experiment.Colorimeter and Fourier transform infrared absorption spectrum(FT-IR)were used to mesure the textiles before and after aging,and Ultra-High-Performance Chromatography-quadrupole-time-of-flight mass spectrometry(UHPLC-Q-Tof-MS)was used to determine the changes of dye components before and after aging,which laid a foundation for studying the aging and fading mechanism of these common dyes.Since the UHPLC-Q-Tof-MS method has ultra-high resolution and is suitable for the low content of textile relics and dye samples,this study uses this technique as the main analysis method.In the analysis of dyes by UHPLC-Q-Tof-MS method,it is the key to select an appropriate solvent to effectively extract the dyes on textile fibers.In this study,a two-step extraction method using dimethyl sulfoxide as the solvent was determined through a comparative test extraction method.This method has better extraction effect on dyes on textile fibers due to its strong solubility and mild characteristics.By optimizing the experimental parameters of UHPLC-Q-Tof-MS,combined with two step extraction method of two methylsulfoxide as solvent,the main dye components of various plant dyes before and after photoaging were accurately detected with fewer samples.Through experimental study,the main dyeing components in Rubia cordifolia L.root are anthraquinones,naphthoquinone,and a small amount of triterpenoids.Hematoxylins and chalcones are the main dyeing components in Logwood,also comes with flavonoids such as quercetin.The main dyeing components in Safflower are safflower glycosides.The main dyes in Turmeric are curcumin compounds and a small amount of sesquiterpenoids;The main dyeing components in Gardenia jasminoides are cyclic olefin ether terpenes such as geniposide and geniposide.In addition,there are acid compounds and a small amount of flavonoids such as lutein and rutin.The main dyes in Sophora Japonica are triterpenoid saponins and flavonoids.The main dyeing components in Phellodendron Amurense are alkaloids such as berberine and jatrorrhizine,and a small amount of limonin compounds.The main ingredient used for coloring in Lithospermum erythrorhizon Sieb.et Zucc is naphthoquinones.In this study,glycosides were also detected for the first time in the dyeing components of some plants,such as Rubierythric acid,Curcumin-?-D-Glucuronide in Turmeric,isorhamnetin-3-rutin and kaempferol-3-rutin in Sophora Japonica..In addition,this study also attempts to explore the identification method of alum,a mordant commonly used in ancient textile dyeing.SEM-EDX was used to analyze the dyed textile fibers,and the quality of the analysis results was normalized to determine whether alum was used as mordant in dyeing textiles.Finally,the mature dye extraction method and UHPLC-Q-TOF-MS detection method were applied to the dye identification of several textile cultural relics in the Tang,Ming and Qing Dynasties.The dye used for red and brown silk is Rubia cordifolia L.,and the dye used for blue silk is indigo;the purple silk is dyed with Lithospermum erythrorhizon Sieb.et Zucc..the textiles fragments unearthed from Qinghai Province ware tested and the results showed that the red sample was dyed with Rubia cordifolia L.,and the yellow sample was dyed with Gardenia jasminoides.The textiles unearthed from the tomb of the Ming Dynasty is dyed with Rhubarb.The yellow thread from the package textile in the Qing Dynasty used Gardenia jasminoides as the source of plant dyes.And blue thread is dyed with indigo.For the first time,it was discovered that the green color of the bed cover fabric may originate from Rhamnus davurica Pall..The research results not only improve people's scientific cognition of these precious textile relics,but also provide scientific basis for their restoration...