Microextraction of Reseda luteola-Dyed Wool and Qualitative Analysis of Its Flavones by UHPLC-UV, NMR and MS

Abstract

Detailed knowledge on natural dyes is important for agronomy and quality control as well as the fastness, stability, and analysis of dyed textiles. Weld (Reseda luteola L.), which is a source of flavone-based yellow dye, is the focus of this study. One aim was to reduce the required amount of dyed textile to ≤50 μg for a successful chromatographic analysis. The second aim was to unambiguously confirm the identity of all weld flavones. By carrying out the extraction of 50 μg dyed wool with 25 μL of solvent and analysis by reversed-phase UHPLC at 345 nm, reproducible chromatographic fingerprints could be obtained with good signal to noise ratios. Ten baseline separated peaks with relative areas ≥1% were separated in 6 min. Through repeated polyamide column chromatography and prepHPLC, the compounds corresponding with the fingerprint peaks were purified from dried weld. Each was unequivocally identified, including the position and configuration of attached sugars, by means of 1D and 2D NMR and high-resolution MS. Apigenin-4′-O-glucoside and luteolin-4′-O-glucoside were additionally identified as two trace flavones co-eluting with other flavone glucosides, the former for the first time in weld. The microextraction might be extended to other used dye plants, thus reducing the required amount of precious historical textiles.

Dye Analysis of a 17th-Century Mattens Workshop Tapestry Based on Raphael’s Drawing, The Miraculous Draught of Fishes

“…The dyestuff weld (Reseda luteola) was detected in 31 samples, making it the most prevalent dyestuff identified in the sample yarns from the tapestry. Twelve marker compounds from weld have recently been isolated in sufficiently pure form to allow structural characterization by high-resolution mass spectrometry and two-dimensional proton NMR spectroscopy [22]. Additionally, several publications on the characterization of weld dyestuff on textiles have included chromatograms from reverse phase columns similar to the present study showing consistent relative order of elution and relative peak height of the marker compounds [22][23][24][25][26][27].…”

“…Twelve marker compounds from weld have recently been isolated in sufficiently pure form to allow structural characterization by high-resolution mass spectrometry and two-dimensional proton NMR spectroscopy [22]. Additionally, several publications on the characterization of weld dyestuff on textiles have included chromatograms from reverse phase columns similar to the present study showing consistent relative order of elution and relative peak height of the marker compounds [22][23][24][25][26][27]. By comparison to these data, the corresponding dye markers in the present analyses could be assigned.…”

Noninvasive Characterization and Quantification of Anthraquinones in Dyed Woolen Threads by Visible Diffuse Reflectance Spectroscopy

“…Reverse phase liquid chromatography (LC) separation coupled with the detection of individual components is the most established analytical technique used to obtain reliable information on the source of the dyes. Recent developments using ultrahigh-performance liquid chromatography (UHPLC/UPLC) combined with microextraction or small scale extraction − allow one to significantly reduce the quantity of material required for successful dye analysis. However, these methods still require sampling and acidic extraction, which is often unreasonable in the case of artworks of great importance.…”

Identification of Dyes in Coptic Textiles from the Museum of Faculty of Archaeology, Cairo University

“…The latter often provide enough information to identify the biological source of a dye fixed on a historical or archaeological textile [21]. Several mild acids that retain glycosides have been suggested for dye extraction such as, for instance, formic [22][23][24][25][26][27][28], oxalic [23,[25][26][27]29,[30][31][32], hydrofluoric [25,33] and trifluoroacetic [23,27,34] acids. Other approaches for dye extraction suggested the use of ammonia-disodium EDTA to preserve glycosyl moieties [35] and an aqueous glucose solution for the extraction of madder [36].…”