Inter-laboratory chemical study of natural materials from the historical wiesner collection

Abstract EN

Micro samples of Rubia tinctorum L., Isatis tinctoria L., Indigofera tinctoria L., Opuntia decumana L.

and Caesalpina echinata Lamarck were analyzed independently by five institutions, which applied their own analytical protocols and instrumentation.

Samples were extracted from the historical “Wiesner Raw Material Collection” which is in the ownership of the Vienna University of Technology.

Two analytical techniques were employed; High Performance Liquid Chromatography (HPLC) and Pyrolysis Capillary Gas Chromatography/Mass Spectrometry (Py-CGC / MS).

For the HPLC experiments, samples were treated with acidified methanol, a method which is extensively used to extract dyes from (historical) textile fibers.

For the Py-CGC / MS studies no sample treatment was necessary.

Coloring compounds, which are used as indices for the assessment of dyestuff sources, were identified in all samples and with almost all analytical protocols.

Comparable results were obtained with both analytical techniques, HPLC and Py-CGC / MS.