Cultural Heritage Agency of the Netherlands RCE

Amersfoort, Netherlands

Cultural Heritage Agency of the Netherlands RCE

Amersfoort, Netherlands

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Serrano A.,Cultural Heritage Agency of the Netherlands RCE | Serrano A.,University of The Azores | van den Doel A.,Cultural Heritage Agency of the Netherlands RCE | van den Doel A.,Radboud University Nijmegen | And 4 more authors.
Analytica Chimica Acta | Year: 2015

The colorant behaviour of cochineal and kermes insect dyes in 141 experimentally-dyed and 28 artificially-aged samples of silk and wool was investigated using ultra-high performance liquid chromatography coupled to photodiode array detector (UHPLC-PDA), liquid chromatography electrospray ionisation mass spectrometry (LC-ESI-MS) and image scanning electron microscopy - energy dispersive X-ray spectroscopy (SEM-EDX). Partial-least squares discriminant analysis (PLS-DA) was then used to model the acquired UHPLC-PDA data and assess the possibility of discriminating cochineal insect species, as well as their correspondent dyed and aged reference fibres. The resulting models helped to characterize a set of 117 red samples from 95 historical textiles, in which UHPLC-PDA analyses have reported the presence of cochineal and kermes insect dyes. Analytical investigation of the experimentally-dyed and artificially-aged fibres has demonstrated that the ratio of compounds in the insects dye composition can change, depending on the dyeing conditions applied and the type of fibres used. Similarities were observed when comparing the UHPLC-MS and SEM-EDX results from the dyed and aged references with the historical samples. This was verified with PLS-DA models of the chromatographic data, facilitating the classification of the cochineal species present in the historical samples. The majority of these samples were identified to contain American cochineal, which is in agreement with historical and dye identification literature that describe the impact of this dyestuff into European and Asian dyeing practices, after the Iberian Expansion in the 16th century. The analytical results emphasize the importance of using statistical data interpretation for the discrimination of cochineal dyes, besides qualitative and quantitative evaluation of chromatograms. Hence, the combination of UHPLC-PDA with a statistical classification method, such as PLS-DA, has been demonstrated to be an advisable approach in future investigations to assess closely related species of natural dyes in historical textile samples. This is particularly important when aiming to achieve more accurate interpretations about the history of works of art, or the application of natural dyes in old textile production. © 2015 Elsevier B.V.


PubMed | University of Amsterdam, Cultural Heritage Agency of the Netherlands RCE, University of The Azores and Radboud University Nijmegen
Type: | Journal: Analytica chimica acta | Year: 2015

The colorant behaviour of cochineal and kermes insect dyes in 141 experimentally-dyed and 28 artificially-aged samples of silk and wool was investigated using ultra-high performance liquid chromatography coupled to photodiode array detector (UHPLC-PDA), liquid chromatography electrospray ionisation mass spectrometry (LC-ESI-MS) and image scanning electron microscopy - energy dispersive X-ray spectroscopy (SEM-EDX). Partial-least squares discriminant analysis (PLS-DA) was then used to model the acquired UHPLC-PDA data and assess the possibility of discriminating cochineal insect species, as well as their correspondent dyed and aged reference fibres. The resulting models helped to characterize a set of 117 red samples from 95 historical textiles, in which UHPLC-PDA analyses have reported the presence of cochineal and kermes insect dyes. Analytical investigation of the experimentally-dyed and artificially-aged fibres has demonstrated that the ratio of compounds in the insects dye composition can change, depending on the dyeing conditions applied and the type of fibres used. Similarities were observed when comparing the UHPLC-MS and SEM-EDX results from the dyed and aged references with the historical samples. This was verified with PLS-DA models of the chromatographic data, facilitating the classification of the cochineal species present in the historical samples. The majority of these samples were identified to contain American cochineal, which is in agreement with historical and dye identification literature that describe the impact of this dyestuff into European and Asian dyeing practices, after the Iberian Expansion in the 16th century. The analytical results emphasize the importance of using statistical data interpretation for the discrimination of cochineal dyes, besides qualitative and quantitative evaluation of chromatograms. Hence, the combination of UHPLC-PDA with a statistical classification method, such as PLS-DA, has been demonstrated to be an advisable approach in future investigations to assess closely related species of natural dyes in historical textile samples. This is particularly important when aiming to achieve more accurate interpretations about the history of works of art, or the application of natural dyes in old textile production.


Lauwerier R.C.G.M.,Cultural Heritage Agency of the Netherlands RCE
Livestock Science | Year: 2015

Most cattle in the Netherlands have been deliberately dehorned, which some people consider to be a cruel practice. But the breeding of genetically hornless (or polled) cattle is also regarded as unnatural and cruel to animals. Nevertheless, this is a practice which, like elsewhere in Europe, was also common here in the past. Unlike elsewhere in Europe, in the Netherlands polledness, a dominant trait, occurred mainly in the Roman period and disappeared again in the Middle Ages. Polled cattle were particularly common in the coastal area beyond the borders of the Roman Empire, where up to 40% of animals were hornless. By contrast, to the south of the border, polled cattle were rare. No polled animals have so far been found in Nijmegen, at the time the country's most important military and civilian centre. The question is why this is the case, and why polled cattle subsequently disappeared from the Netherlands.There is little evidence to explain the presence of polled cattle on one side of the Roman border, their near absence on the other, and their total disappearance after the Roman period on the basis of natural selection. Nor do functional considerations - superiority as a source of food or supplier of tractive power - provide us with any conclusive answers. The most likely explanation is that it was mainly emotional and aesthetic considerations that led farmers and other users of cattle to decide what a 'good' cow was, and that was a cow with horns. The fact that polled cattle occurred in the coastal area during the Roman period may be associated with a different ideal, and possibly also with a lack of economic power that prevented farmers from being selective. After the Roman period, the desire for 'good' horned cattle will have caused the disappearance of the dominant polled cattle. A growing demand for horn as a raw material for the manufacture of objects might also have played a role. These factors should probably be viewed in the context of an influx of other breeds brought by new population groups that 'drove out' the old cattle populations. The current debate in the Netherlands as to the desirability of breeding polled cattle would appear to be nothing new, having already exercised the minds of farmers centuries ago. © 2015 Elsevier B.V.


Serrano A.,Cultural Heritage Agency of the Netherlands RCE | Serrano A.,University of The Azores | Van Bommel M.,Cultural Heritage Agency of the Netherlands RCE | Hallett J.,University of The Azores
Journal of Chromatography A | Year: 2013

An evaluation was undertaken of ultrahigh pressure liquid chromatography (UHPLC) in comparison to high-performance liquid chromatography (HPLC) for characterizing natural dyes in cultural heritage objects. A new UHPLC method was optimized by testing several analytical parameters adapted from prior UHPLC studies developed in diverse fields of research. Different gradient elution programs were tested on seven UHPLC columns with different dimensions and stationary phase compositions by applying several mobile phases, flow rates, temperatures, and runtimes. The UHPLC method successfully provided more improved data than that achieved by the HPLC method. Indeed, even though carminic acid has shown circa 146% higher resolution with HPLC, UHPLC resulted in an increase of 41-61% resolution and a decrease of 91-422% limit of detection, depending on the dye compound. The optimized method was subsequently assigned to analyse 59 natural reference materials, in which 85 different components were ascribed with different physicochemical properties, in order to create a spectral database for future characterization of dyes in cultural heritage objects. The majority of these reference samples could be successfully distinguished with one single method through the examination of these compounds' retention times and their spectra acquired with a photodiode array detector. These results demonstrate that UHPLC analyses are extremely valuable for the acquisition of more precise chromatographic information concerning natural dyes with complex mixtures of different and/or closely related physicochemical properties, essential for distinguishing similar species of plants and animals used to colour cultural heritage objects. © 2013 Elsevier B.V.

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