Chieli A, Sanyova J, Doherty B, Brunetti B G, Miliani C
Università degli Studi di Perugia c/o Dipartimento di Chimica, Biologia e Biotecnologie, Via Elce di Sotto 8, Perugia, Italy.
Institut Royal du Patrimoine Artistique (IRPA-KIK, Belgium), 1, Parc du Cinquantenaire, 1000 Brussels, Belgium.
Spectrochim Acta A Mol Biomol Spectrosc. 2016 Jun 5;162:86-92. doi: 10.1016/j.saa.2016.03.007. Epub 2016 Mar 9.
In this work a combined chromatographic and spectroscopic approach is used to provide a diagnostic assessment of semi-synthetic ammoniacal cochineal through the syntheses of its dyes and lakes according to art historical recipes. Commercially introduced in the late XIX century as a dye and pigment, it was used to obtain a brilliant purplish/violet nuance which provided a more stable option over carminic acid although its evidenced use in manufacts and artworks of heritage importance have been scarcely documented. Through HPLC-DAD, it has been possible to identify 4-aminocarminic acid as the main component of ammoniacal cochineal highlighting a chemical formula analogous to acid stable carmine, a recent patented food dye. FTIR clearly distinguishes the amine group in the ammoniacal cochineal dye preparation and TLC-SERS allows for an adequate separation and spectral differentiation in its main components to be evidenced. Colloidal SERS has permitted spectral markers useful in discerning ammoniacal cochineal over carminic acid to be highlighted and discussed. Finally, the methods experimented in this study for the identification of ammoniacal cochineal have been validated on analyzing a sample of dyed wool.
在这项工作中，采用了色谱和光谱相结合的方法，根据艺术史配方合成半合成氨胭脂虫红的染料和色淀，以对其进行诊断评估。它于19世纪末作为染料和颜料商业化推出，用于获得明亮的紫/紫罗兰色调，与胭脂红酸相比，它提供了一种更稳定的选择，尽管其在具有重要历史意义的制品和艺术品中的实际使用情况鲜有文献记载。通过高效液相色谱-二极管阵列检测法（HPLC-DAD），已能够鉴定出4-氨基胭脂红酸是氨胭脂虫红的主要成分，突出显示其化学式类似于一种最近获得专利的食品染料——酸稳定型胭脂红。傅里叶变换红外光谱（FTIR）能清晰区分氨胭脂虫红染料制剂中的胺基，薄层色谱-表面增强拉曼光谱（TLC-SERS）则能对其主要成分进行充分分离并证明其光谱差异。胶体表面增强拉曼光谱（Colloidal SERS）突出显示并讨论了可用于区分氨胭脂虫红和胭脂红酸的光谱标记。最后，本研究中用于鉴定氨胭脂虫红的方法在分析一块染色羊毛样品时得到了验证。
