Yarn samples from the Saltzman Collection of Peruvian dyes were characterized by several different analytical techniques: high performance liquid chromatography with both diode array detection ...(HPLC-DAD) and electrospray ionisation with tandem mass spectrometry (HPLC-ESI-Q-ToF), direct analysis in real time (DART) mass spectrometry and paper spray mass spectrometry. This report serves primarily as a database of chemical information about the colorants in these dye materials for those studying ancient South American textiles and their colorants. We also provide a comparison of the results obtained by currently widespread HPLC techniques with those of two different ambient ionisation direct mass spectrometry methods to highlight the advantages and disadvantages of these approaches.
The complex and colorful textiles of ancient Peru have long been a focus of technical study, particularly to characterize the sources of the wide variety of dyes utilized by these Andean artisans. ...This manuscript describes the characterization of the dyes of both primary (red, blue, and yellow) and secondary (purple, orange, and green) colors sampled from textiles spanning five major civilizations: the Paracas Necropolis, the Nazca, the Wari, the Chancay, and the Lambayeque, all from Peru. All but the Paracas Necropolis samples were part of technical conservation studies of the ancient South American textiles collections of the Michael C. Carlos Museum. Analysis of the dyes was carried out utilizing direct analysis in real time time-of-flight mass spectrometry (DART-MS) and paper spray MS. To validate these ambient ionization MS methods, the samples were further investigated using high-performance liquid chromatography (HPLC) with ultraviolet-visible diode array detection (DAD). These results show that ambient ionization MS methods are simple and fast for characterization of the general classes of dyes, e.g., plant reds vs. insect reds, and indigoids in blues and greens. Due to the myriad possible sources of yellow dyes and their tendency to undergo oxidative decomposition, positively identifying those components in these yarns was difficult, though some marker compounds and flavonoid decomposition products were readily identified by ambient ionization mass spectrometry.
We present here a method requiring no sample preparation for direct identification of the organic dye compounds quercetin, indigotin, and alizarin in reference materials, in solution, and also in ...situ in dyed fibers by use of direct analysis in real time (DART) ionization and high-resolution time-of-flight mass spectrometry. Exact mass determinations on small samples of dyed textiles were completed in less than 1 min. With the ability to identify flavonoid, indigoid, and anthraquinone classes of dyes, this technique shows early promise as an additional analytical tool in the challenging analysis of organic dyes in rare cultural heritage materials and possesses the unique advantages of sensitivity and simplicity without the preparatory procedures required by other methods.
Since 2005 we have been utilizing accelerator mass spectrometry (AMS) 14C dating in research on calcium oxalate crusts associated with open air rock art of the Iberian Peninsula. In this paper we ...present two dates linked with three eye-idol pictographs at Abrigo de los Oculados (Henarejos, Cuenca, Spain). Radiocarbon ages for these motifs agree with the expected iconography-based archaeological chronology. Such oxalate dates could provide an independent basis for evaluating chronological theories for post-Palaeolithic sites, designated in the UNESCO World Heritage List as Rock Art of the Mediterranean Basin on the Iberian Peninsula.
► Two samples from a site with prehistoric rock art have been radiocarbon dated. ► Samples were collected from accretionary crusts of calcium oxalate. ► Samples were in stratigraphic relationship with three Schematic ‘eye-idols’. ► Ante quem and post quem radiocarbon dates were obtained. ► Radiocarbon dates are coherent and in agreement with expectations.
Prior to exhibiting an African Komo mask from the collections of the Detroit Institute of Arts, a multianalytical approach was undertaken to characterize the flaking encrusted coating on the surface ...of the mask. Preliminary XRF and FTIR examination of the coating on the Komo mask revealed the presence of significant quantities of iron and protein, possibly indicating the presence of blood. Raman spectroscopy showed evidence for the porphyrin structure of haem as well. To confirm that blood was indeed present in the coating, we developed a novel method for identifying the haem moiety from blood by use of in situ methylation and direct analysis in real time mass spectrometry (DART-MS). Following a denaturing step with formic acid, the resulting solution was combined with an excess of phenyltrimethylammonium hydroxide to promote desorption, applied to a melting point tube, and placed into the direct analysis in real time ion source gas stream at 550 °C. The permethylated haem ion (m/z 644.208) from myoglobin, haemoglobin, fresh blood, and blood aged in the laboratory for 10 years was readily observed above the background. By the described DART-TOF-MS method, permethylated haem was positively identified in the mask coating, confirming the presence of blood. This method has obvious utility in forensic science beyond that for identifying blood incorporated in cultural heritage materials.
The Paracas Necropolis on the south coast of Peru is renowned for the elaborate funerary bundles recovered from that dry sandy region. These bundles contained the remains of male leaders within the ...Paracas communities surrounded by multiple layers of plain cloth and garments with embroidered designs. The methods and materials used in dyeing the yarns used to embellish these ancient fabrics are still not well understood, and the research presented herein seeks to add to that body of knowledge. To investigate the sources of dye colourants in samples from Paracas Necropolis textiles, we applied direct analysis in real time-time-of-flight mass spectrometry (DART-MS). This new methodology has both advantages (analyses are rapid and require little or no sample preparation) and disadvantages (e.g. inability to identify intact carminic acid) compared to existing ones used in the analysis of dye colourants. Direct analysis in real time mass spectra were collected on chemical standards, botanical materials and comparative reference samples prepared with Relbunium roots and cochineal insects (Dactylopius sp.), and the results are compared to red fibres obtained from several different textiles within two different funerary bundles from the Museo Nacional de Arqueología Antropología e Historia in Lima, Peru. The results from the DART-MS analysis of these red fibres show that the compounds present are consistent with the presence of dye obtained from Relbunium species, and cochineal insects were not used to colour these fibres.
Statement of significance DART-MS is an efficient and effective method to identify red colourant composition in small samples of fibres removed from archaeological textiles. Of significant note is the ability to differentiate isomers present in Relbunium and other anthraquinone dyes. Colourants in Relbunium are readily distinguished. Although a component of carminic acid from cochineal is less reliably positively identified by DART-MS, it is possible to use a simple extraction and ionization method to confirm or exclude the presence of carminic acid. Relbunium and cochineal are known to have been used in Paracas textiles. Not only does DART-MS aid in identification of colourants using small amounts of material and without significant sample preparation, the information can be used to distinguish fibres that were prepared differently thus indicating past knowledge of dyeing technology. The information can also aid in separating periods of artefact manufacture, and guide development of a conservation strategy.
Utilizing archaeometric methods, we evaluate the nature of production of feasting events in the ancient Wari state (600–1000 CE). Specifically, we focus on the fabrication of ceramic serving and ...brewing wares for the alcoholic beverage chicha de molle. We examine the source materials used in the creation of these vessels with elemental analysis techniques (INAA and LA-ICP-MS). We then assess the chemical traces of the residues present in the ceramic pores of the vessels to detect compounds indicative of the plants used in chicha production (DART-MS).While previous research has identified circumstantial evidence for the use of Schinus molle in the production process, this research presents direct evidence of its existence in the pores of the ceramic vessels. We also assess what this material evidence suggests about the sustainability of the feasting events as a mode of political interaction in the Wari sphere. Our evaluation indicates that regional resource use in the production of the ceramic vessels promoted locally sustainable raw material procurement for the making of the festivities. Likewise, drought resistant crops became the key ingredients in the beverages produced and provided a resilient harvest for chicha production that was adopted by successor groups.
Examination of fibers from a colored fabric fragment from Seip Mound Group, Ohio, demonstrates the utility of sequencing analytical techniques: (1) minimally destructive pretreatment to remove humic ...acids followed by plasma-chemical oxidation, in preparation for accelerator mass spectrometric determination of radiocarbon age and (2) direct analysis in real time mass spectrometry (DART-MS) of the pretreatment solution, for the determination of red colorants. Pretreatment followed by plasma-chemical oxidation provided the opportunity to date 3 mg of fiber using just 200 mcg of carbon. Examination of the pretreatment solution by DART-MS confirmed the composition of anthraquinones consistent with those from bedstraw root (Galium sp.). The date determined (1,805 ± 35 B.P.) places the textile in the midrange of radiocarbon dates previously obtained for the Seip earthworks; identification of the dye plant shows that the Hopewell possessed a sophisticated knowledge of plants and their uses.
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