As Straight as a dye

Chromatographic analyses in Pisa

A huge section of this project is dedicated to the understanding of dyes in Andean khipus. We know that colour played an essential role in conveying qualitative information in the khipu semiotics. “The problem is that we don’t know ‘how'” you might have imagined.

Yes. But there’s more. The huge problem with colour, as silly as it might sound to point out, it that it fades in time. And it fades according to multiple co-interacting factors (acidity of the soil, humidity, mordanting techniques, light exposure …).

Therefore, if we really want to think about the role of colour in Andean khipus, we first need to understand how they have been coloured.
For this reason, after all the preliminary morphological studies, technical photography evaluations, and XRF mappings, some khipu samples in this project have been selected for chromatographic analyses.

Samples from a khipu after chromatographic extraction

From 10th to 15th July 2022 I was in Pisa at the Science for Cultural Heritage (SCICH) laboratory in the Department of Chemistry. Here I collaborated with Ilaria Degano, Associate Professor in Analytical Chemistry with an expert and unique knowledge of native South American dyes.

Prof Ilaria Degano preparing the samples for HPLC

Liquid chromatography coupled with diode array detector and with high-resolution mass spectrometry (HPLC–DAD, HPLC–HRMS) was performed for characterizing organic dye composition.

This was the first time ever khipu dyes have been analyzed and identified and will be a unique contribution to our current limited understanding of khipu meaningful colours.

The team and I can’t wait to present the first results coming out of this research in the Dyes in History and Archaeology conference!
Check all the details, the program and how to participate here!