Unlocking the secrets of historical violet hues: A spectroscopic and mass spectrometric investigation of logwood ink recipes

IF 4.1 3区工程技术 Q2 CHEMISTRY, APPLIED

Dyes and Pigments Pub Date : 2025-03-13 DOI:10.1016/j.dyepig.2025.112757

Adele Ferretti , Eva Vermeersch , Francesca Sabatini , Ilaria Degano , Peter Vandenabeele

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引用次数: 0

Abstract

The spread of logwood bark (Heamatoxylum campechianum L.) in Europe as a dyestuff dates back to the 16^th century, while its integration into ink formulations only began in the 19^th century (logwood inks). Renowned for their broad spectrum of achievable colours and their non-corrosive impact on paper, logwood inks have been used by many artists, for instance by Impressionists in their drawings. This work investigates the gap in the literature related to the chemical composition of logwood-based inks, specifically focusing on the comprehensive characterisation of dye components and the influence of recipes on the inks molecular profile. Several 19^th-20^th century formulations of logwood inks, differing in inorganic salts, additives and pre-oxidation time, were selected and reproduced according to historical recipes. Colourimetric measurements enabled us to evaluate the chromatic differences of logwood-based inks produced following historical methods. Instead, the organic component was investigated on reference mock-ups by analytical methods based on micro-Raman spectroscopy and liquid chromatography coupled to diode array detection (HPLC-DAD) and high-resolution tandem mass spectrometry (HPLC-ESI-Q-ToF) after suitable sample treatments. Raman analysis revealed significative shifts in vibrational modes of dyes depending on the inorganic salts used in the recipes, providing a unique fingerprint able of distinguishing alum-, alum/copper-, iron-, and chrome-based logwood inks. Additionally, HPLC-DAD and HPLC-ESI-Q-ToF enabled us to expand the dataset of molecular markers available for logwood inks identification, by tentatively assigning the structure of compounds never or seldom reported in the literature (G-compounds and hematein derivatives). The potential synergy of spectroscopic and chromatographic techniques was also explored, allowing us to achieve valuable insights on the oxidation pathway of hematoxylin to hematein (both C.I. 75290) in relation to the ink recipes. The proposed method is particularly valuable in forensic and heritage science, where the composition of inks can offer crucial insights into the origin and authenticity of documents or artworks.

查看原文本刊更多论文

揭开历史上紫罗兰色调的秘密：对原木油墨配方的光谱和质谱调查

原木树皮（Heamatoxylum campechianum L.）作为染料在欧洲的传播可以追溯到16世纪，而将其整合到油墨配方中直到19世纪才开始（原木油墨）。原木墨水以其广泛的可实现色彩范围和对纸张的无腐蚀性影响而闻名，许多艺术家都使用原木墨水，例如印象派画家在他们的绘画中使用原木墨水。这项工作调查了与原木基油墨化学成分相关的文献空白，特别关注染料成分的综合表征和配方对油墨分子谱的影响。几种19 -20世纪的原木油墨配方，在无机盐、添加剂和预氧化时间上有所不同，根据历史配方进行了选择和复制。比色测量使我们能够评估根据历史方法生产的原木基油墨的色差。在样品处理后，采用基于微拉曼光谱和液相色谱耦合二极管阵列检测（HPLC-DAD）和高分辨率串联质谱（HPLC-ESI-Q-ToF）的分析方法在参考模型上对有机成分进行了研究。拉曼分析揭示了染料振动模式的显著变化，这取决于配方中使用的无机盐，提供了一个独特的指纹，能够区分明矾、明矾/铜、铁和铬基木材油墨。此外，HPLC-DAD和HPLC-ESI-Q-ToF通过初步确定文献中从未或很少报道的化合物（g -化合物和血红素衍生物）的结构，使我们能够扩展可用于原木油墨鉴定的分子标记数据集。我们还探索了光谱和色谱技术的潜在协同作用，使我们能够对苏木精氧化为血红素的途径（两者都是C.I. 75290）与油墨配方的关系获得有价值的见解。这种方法在法医和文物科学中特别有价值，因为墨水的成分可以为了解文件或艺术品的来源和真实性提供重要的见解。

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来源期刊

Dyes and Pigments 工程技术-材料科学：纺织

CiteScore

8.20

自引率

13.30%

发文量

933

审稿时长

33 days

期刊介绍： Dyes and Pigments covers the scientific and technical aspects of the chemistry and physics of dyes, pigments and their intermediates. Emphasis is placed on the properties of the colouring matters themselves rather than on their applications or the system in which they may be applied. Thus the journal accepts research and review papers on the synthesis of dyes, pigments and intermediates, their physical or chemical properties, e.g. spectroscopic, surface, solution or solid state characteristics, the physical aspects of their preparation, e.g. precipitation, nucleation and growth, crystal formation, liquid crystalline characteristics, their photochemical, ecological or biological properties and the relationship between colour and chemical constitution. However, papers are considered which deal with the more fundamental aspects of colourant application and of the interactions of colourants with substrates or media. The journal will interest a wide variety of workers in a range of disciplines whose work involves dyes, pigments and their intermediates, and provides a platform for investigators with common interests but diverse fields of activity such as cosmetics, reprographics, dye and pigment synthesis, medical research, polymers, etc.