Blue natural organic dyestuffs—from textile dyeing to mural painting. Separation and characterization of coloring matters present in elderberry, logwood and indigo

Abstract

Natural dyestuffs used for painting or dyeing of textiles are complex mixtures of compounds of various chemical properties. Proper identification of the dye used by a painter and, even better, its origin is possible only when its compositional 'fingerprint' can be evaluated. For this reason gradient program for liquid chromatographic separation of 16 color compounds--components of natural blue dyes: elderberry, logwood and indigo--has been developed. Two detector systems were used simultaneously: UV-Vis spectrophotometry (at 280, 445, 520 and 600 nm) and ESI mass spectrometry (positive and negative SIM mode). It was found that fragmentation observed in ESI-MS is affected not only by ion source parameters, but also by chromatographic conditions, especially in case of the less stable substances: cyanidin glucosides, tannic acid, rutin and hematoxylin. Examination of characteristic dissociation pathways of the compounds under investigation after direct admission into ion source or after chromatographic separation allowed to select proper ions for SIM detection and to develop novel and efficient reversed phase high performance liquid chromatographic (RP-HPLC)-UV-Vis/ESI-MS method for the analysis of natural blue dyes. The procedure was successfully applied for identification of indigotin and carminic acid-main colorants extracted from a fiber taken from the blue-red 'Italian' tapestry (the collection of the National Museum in Warsaw, Poland).

Extracting natural dyes from wool—an evaluation of extraction methods

“…Arraiolos recipes refer the use of weld and indigo to dye wool fibres in green hues [34]. The identification of indigotin as the chromatographic peak eluting at approximately 26.50 min was done based on its characteristic UV-Vis and mass spectra [12,44,45]. As reported in the literature [12,45] [2].…”

Historical and archaeological textiles: An insight on degradation products of wool and silk yarns

“…In particular, the application of micro destructive methods entailing a solvent extraction from the matrix (i.e., lake substrate or yarns), followed by separation techniques, was the choice of election for their characterisation in most of the cases. The target chromophore-containing molecules are polar, water-soluble molecules; thus, the most widely used technique is reverse phase liquid chromatography HPLC with diode array detectors [25,26] often coupled with MS detectors [27][28][29][30][31][32][33][34][35][36][37][38]. Fluorescence spectrophotometers were also used as sensitive and selective detectors [39][40][41].…”

Investigation of the colourants used in icons of the Cretan School of iconography

“…Natural organic colouring materials used in objects of the cultural heritage are identified by electrochemical methods [18][19][20] and more commonly by high performance liquid chromatography (HPLC) equipped with diode array detector (DAD) [21][22][23][24][25][26][27][28][29][30][31] and/or mass spectrometry (MS) [32][33][34][35][36][37][38][39][40][41][42][43][44][45]; HPLC with fluorescence detection has been also used [46]. Prior to HPLC analysis, samples have to be treated to extract and solubilise the contained dyestuffs.…”