Portland State University. Department of Chemistry
Tami Lasseter Clare
Term of Graduation
Date of Publication
Doctor of Philosophy (Ph.D.) in Chemistry
Chilkat, Dyes, Instrumentation, Mass Spectrometry, Mordants, XRF
1 online resource (xiii, 182 pages)
The project goal is to identify the dyestuffs used in hand-woven Chilkat blankets from the collection of the Alaska State Museum and the Sheldon Jackson Museum. Chilkat weaving is practiced by Northwest coastal clans, particularly in Southeast Alaska since at least the early 19th century. Through this collaboration, 117 wool fibers from 23 Chilkat textiles, and 193 reference samples consisting of dyed fibers using both natural and synthetic dye sources, raw dye material, and dye bath aliquots were provided to the lab for reference characterization and identification. In these analyses, dyes were classified as being either natural or synthetic, subdivided into dye types, such as flavonoid or azo, and sometimes exactly identified such as synthetic triarylmethane dye brilliant green. By classifying or identifying dyes, some of the provenance of textiles, such as the earliest date of manufacture, may be determined based on when the dye was first synthesized or commercialized. One of the ethical principles guiding cultural heritage research requires that very little sample be taken from the studied object in order to preserve its cultural and aesthetic value. For this reason, it is necessary to develop an analytical pathway that maximizes the dye information obtained by analyzing microsamples, starting with non-destructive methods and proceeding to destructive methods.
During this investigation, several analytical methods were assessed and compared to test their independent strengths, relative weaknesses, and complementary relationships. This evaluation resulted in the proposed analytical pathway, which is separated into two categories. Category 1 is defined by non-destructive fiber examination using visual color analysis, x-ray fluorescence, and Direct Analysis in Real Time Mass Spectrometry (DART-MS). X-ray fluorescence was utilized to provide elemental data that may indicate the presence of metal-containing dyes, mordants, or other dye bath additives, while DART-MS provided molecular information related to dye components. Standard optical microscopy provided early characterization of the fiber collection based on visual color alone. Category 2 is defined by destructive methods with and without chromatographic separation. Gas Chromatography Mass Spectrometry (GCMS) was used with either liquid dye extractions, or with fiber pyrolysis (pyro-GCMS). Electrospray Ionization Mass Spectrometry (ESI-MS) was utilized for non-separation dye extraction analysis. SERS may also be performed on dye extractions used from other analytical methods for additional dye characterization. This project specifically focuses on methods that are more novel for this purpose, compared to the typical liquid chromatography and spectrophotometric techniques.
©2023 Dario Gerlando Durastanti
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Durastanti, Dario Gerlando, "Developing a Sample-efficient Analytical Pathway for a Qualitative Chemical Investigation of Ancestral Chilkat Dyeing and Weaving Practices" (2023). Dissertations and Theses. Paper 6420.
Available for download on Saturday, May 17, 2025