For dyeing yarns used in the production of tapestries, one of the most important source during the centuries was the root of madder (Rubia tinctorum L.). Madder root contains a large number of compounds characterized by anthraquinone structures, which give to the yarn a red hue. The main chromophore compounds, often in glycosylated form, are: 1,2-dihydroxy-anthraquinone (alizarin, orange colour); 1,2,4-trihydroxy- anthraquinone (purpurin, red colour); 1,2,4-trihydroxy-anthraquinone-3-carboxylic acid (pseudopurpurin, red-brownish colour; 1,2,3-trihydroxy-anthraquinone (anthragallol, orange colour). During the dyeing process, however, also other types of molecules (not necessarily anthraquinones), present in the matrix, are fixed on the yarn. These substances may be involved in the aging process and their participation in the processes of degradation is currently under investigation. Experimentally it is in fact observed that some compounds show a faster degradation than the others. In order to establish an appropriate restoration, it is necessary to identify all the compounds involved and then clarify the mechanisms of degradation. In this work, it has carried out extraction of dyes from textile fibers coming from some tapestries in the Vatican Museums; extracts has been analysed by HPTLC, 1H-NMR and ESI-MS. First, madder’s root extract has been obtained in the same conditions of dye bath. This extract has been studied through LC and both 1H-NMR. Fractions obtained were compared with extracts from historical yarns and “contemporary textiles” dyed according to original recipes. This comparison has been carried out through HPTLC. In this way, it highlighted which bands were present in madder’s roots and in the yarn’s extracts. The most interesting samples were chromatographed through TLC technique and the resulting bands were extracted and solubilized in a 1:1 mixture of acetonitrile and 0.3% formic acid in water. Then, ESI-MS and ESI-MSn experiments were performed. Through this technique, we obtain the full spectrum with the value of m/z for every compound contained in a fraction and then we can fragment every single peak to clarify the structural profile of the same. Specifically, we show here two examples of the use of ESI-MSn tecnique for the identification of hydroxy hydroxy-methyl anthraquinone and glycosyl asperulosidic acid.

Migliore Comunicazione Poster, Ilaria Serafini et al.,“Methodology for the identification of organic dyes used in tapestries”, Abstract “5th CMA4CH Mediterraneum Meeting” / Serafini, Ilaria; Guiso, Marcella; Bianco, Armandodoriano. - (2015).

Migliore Comunicazione Poster, Ilaria Serafini et al.,“Methodology for the identification of organic dyes used in tapestries”, Abstract “5th CMA4CH Mediterraneum Meeting”.

SERAFINI, ILARIA;GUISO, Marcella;BIANCO, Armandodoriano
2015

Abstract

For dyeing yarns used in the production of tapestries, one of the most important source during the centuries was the root of madder (Rubia tinctorum L.). Madder root contains a large number of compounds characterized by anthraquinone structures, which give to the yarn a red hue. The main chromophore compounds, often in glycosylated form, are: 1,2-dihydroxy-anthraquinone (alizarin, orange colour); 1,2,4-trihydroxy- anthraquinone (purpurin, red colour); 1,2,4-trihydroxy-anthraquinone-3-carboxylic acid (pseudopurpurin, red-brownish colour; 1,2,3-trihydroxy-anthraquinone (anthragallol, orange colour). During the dyeing process, however, also other types of molecules (not necessarily anthraquinones), present in the matrix, are fixed on the yarn. These substances may be involved in the aging process and their participation in the processes of degradation is currently under investigation. Experimentally it is in fact observed that some compounds show a faster degradation than the others. In order to establish an appropriate restoration, it is necessary to identify all the compounds involved and then clarify the mechanisms of degradation. In this work, it has carried out extraction of dyes from textile fibers coming from some tapestries in the Vatican Museums; extracts has been analysed by HPTLC, 1H-NMR and ESI-MS. First, madder’s root extract has been obtained in the same conditions of dye bath. This extract has been studied through LC and both 1H-NMR. Fractions obtained were compared with extracts from historical yarns and “contemporary textiles” dyed according to original recipes. This comparison has been carried out through HPTLC. In this way, it highlighted which bands were present in madder’s roots and in the yarn’s extracts. The most interesting samples were chromatographed through TLC technique and the resulting bands were extracted and solubilized in a 1:1 mixture of acetonitrile and 0.3% formic acid in water. Then, ESI-MS and ESI-MSn experiments were performed. Through this technique, we obtain the full spectrum with the value of m/z for every compound contained in a fraction and then we can fragment every single peak to clarify the structural profile of the same. Specifically, we show here two examples of the use of ESI-MSn tecnique for the identification of hydroxy hydroxy-methyl anthraquinone and glycosyl asperulosidic acid.
File allegati a questo prodotto
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/854162
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact