Identification Of Dyestuffs Research Articles

Analysis and identification of dyestuffs in historic Chinese textiles

Analysis and identification of dyestuffs in historic Chinese textiles

Interfaced SEM and micro-Raman Spectroscopy for SERS Analysis of Dyes on Single Fibers

The identification of dyestuff in ancient textiles often provides a major analytical challenge. High Performance Liquid Chromatography (HPLC) coupled with diode-array detection (DAD) and/or mass spectrometry (MS) is the most used technique for the identification of dye molecules. However, this technique has severe limitations in the study of ancient dyed fibers due to the large amount of sample required [1]. Moreover, chemical extraction processes necessary for HPLC analysis can be detrimental to these severely size-limited and irreplaceable archaeological materials.

Identification of dyestuffs in historical textiles: Strong and weak points of a non-invasive approach

The dyers of the past exploited a number of natural dyestuffs and dyeing procedures to obtain countless beautiful colours. It is hard to disclose which dyestuff has been used to dye a historical or an archaeological textile through non-invasive analytical techniques; therefore invasive analytical strategies, which require sampling, are generally employed to face this task. Some useful indication may nevertheless derive from the electronic transitions of dyes supported on the fibres and the signals can be easily recorded by reflectance spectroscopy in the visible range of the electromagnetic spectrum. The use of portable instruments equipped with fibre optics allows operation in-situ directly on the surface of the samples, through a non-invasive approach which is particularly suitable for the inspection of historical or archaeological samples. In this paper, the strong and weak points of visible fibre optics reflectance spectroscopy are discussed, in order to highlight its possible application as a first non-invasive step of a multi-technique analytical strategy devoted to the recognition of natural dyestuffs in ancient textile artefacts. Visible fibre optics reflectance spectra were collected from a large set of reference samples (wool and silk) coloured through various dyestuffs and dyeing procedures, in order to identify the signals of the coloured species that impregnate the fibres. The position of minimum, maximum and inflection points in the reflectance spectra was evaluated and critically discussed, in order to identify the signals which are not contingent to dyeing procedures or to the fibre typology, and that can be therefore confidently used for analytical purposes. In particular, wavelength intervals were defined, in which the characteristic signals of the investigated dyestuffs (indigo, woad, Saxon blue, logwood, cochineal, madder, brazilwood, old fustic, weld, turmeric and saffron) are expected. It emerged that visible fibre optics reflectance spectroscopy is poorly selective for yellow dyes based on curcumins and flavonoids, while it generally succeeds in detecting the other dyestuffs considered herein. The information obtained from the reference sample set was then exploited to analyze an embroidered cloth dated from the seventeenth century. Preliminary information obtained via visible fibre optics reflectance spectroscopy was confirmed, or integrated, by the results obtained through liquid chromatography coupled with diode-array detection and mass spectrometry on extracts obtained from some coloured threads sampled from the historical cloth. 2013 Published by Elsevier Ltd.

Single-Pot Extraction-Analysis of Dyed Wool Fibers with Ionic Liquids

Analytical capabilities to identify dyes associated with structurally robust wool fibers would critically assist crime-scene and explosion-scene forensics. Nondestructive separation of dyes from wool, removal of contaminants, and dye analysis by MALDI- or ESI-MS, were achieved in a single-pot, ionic liquid-based method. Ionic liquids (ILs) that readily denature the wool α-keratin structure have been identified and are conducive to small volume, high-throughput analysis for accelerated threat-response times. Wool dyed with commercial or natural, plant-based dyes have unique signatures that allow classification and matching of samples and identification of dyestuffs. Wool released 0.005 mg of dye per mg of dyed wool into the IL, allowing for analysis of single-thread sample sizes. The IL + dye mixture promotes sufficient ionization in MALDI-MS: addition of common MALDI matrices does not improve analysis of anionic wool dyes. An inexpensive, commercially available tetrabutylphosponium chloride IL was discovered to be capable of denaturing wool and was determined to be the most effective for this readily fieldable method.

Towards the identification of dyestuffs in Early Iron Age Scandinavian peat bog textiles

A large systematic dye investigation of prehistoric Danish and Norwegian bog textiles was carried out using high performance liquid chromatography with photo diode array detection. After the selection of the most suitable protocol for dye extraction and HPLC analysis for this specific group of archaeological samples, the second part included the characterisation of the dyes detected in the whole series of the Early Iron Age textiles and the interpretation of the dyeing technology. Natural organic dyes were found from the three main categories of natural dyes, hence throwing new light on the use of biological dye sources in Early Iron Age Scandinavia. The results clearly indicate that most Scandinavian peat bog textiles originally were dyed and that already during the 1st millennium BC, the populations in Scandinavia were familiar with the dyeing technology.

The Identification of Dyestuffs on Cellulose Acetate

The Identification of Dyestuffs on Cellulose Acetate

The identification of Dyestuffs on Vegetable Fibres.

The identification of Dyestuffs on Vegetable Fibres.

The Identification of Dyestuffs on Animal Fibres

The Identification of Dyestuffs on Animal Fibres