Analysis of Cultural Heritage Objects

Contact: Dr. Signe Vahur, signe.vahur@ut.ee

https://www.ackermann.ee/en/

The research related to cultural heritage objects started in our group in 2003 and is specialized in conservation science, analytical chemistry of cultural heritage materials and more recently also archaeological objects.

Our research interests are investigation and development of methodologies on the basis of different instrumental techniques (ATR-FT-IR, Raman, SEM-EDS, (LA)ICP-MS, MALDI-FT-ICR-MS, ESI-and APCI-FT-ICR-MS, GC-MS etc) for the analysis of cultural heritage and related materials (paints, coatings, dyed textiles, paper components, etc). The methodologies are not limited to cultural heritage materials: they can be used in any field of materials science because the approach is applicable also to other types of materials (for example biological samples, polymers, forensic materials etc).

ATR-FT-IR spectral database

An important advancement from our group is the investigation into the possibilities of analysis of materials related to cultural heritage and conservation science with ATR-FT-IR spectroscopy (ATR-FT-IR) using the extended IR region of 4000-80 cm-1 (mid-IR and far-IR region). During the years ATR-FT-IR spectra of various materials (paints, pigments, binders, coatings, mortars, textiles, etc) have been acquired in the course of different projects on historic, industrial and construction paints and coatings, as well as BSc, MSc and Ph.D. theses. We have assembled these ATR-FT-IR spectra into a library of ATR-FT-IR spectra of various materials, which is available at http://tera.chem.ut.ee/IR_spectra/. This library currently contains over 150 IR spectra and has been described in the article published in the Anal. Bioanal. Chem.

Classification and semi-quantitative analysis of coatings, clothing, silicate minerals and paper

In recent years our work has expanded towards quantitative analysis of materials. In particular, we recently demonstrated the applicability of ATR-FT-IR with PLS data analysis for quantifying the components of paint binders and pigments as well as classification and semi-quantitative ATR-FT-IR analysis of textiles (fabrics). The developed methods were applied to the modern coatings, artistically relevant mixtures and different types of clothing. In recent studies, we have used ATR-FT-IR with PCA data analysis to classification and semi-quantitative analysis of silicate minerals and paper components.

Another important section in method development is dedicated to chromatographic and mass spectrometric techniques and applications for the analysis of resinous materials, textile dyes, paint binders, also to archaeological materials.

Novel MALDI matrices and analysis of resins and archaeological lipids

For the analysis of resinous and varnish materials used in art and archaeology with complementary chromatographic and spectroscopic techniques – ATR-FT-IR, FT-ICR-MS with MALDI, APCI, ESI sources, GC-MS etc. are used. We have developed FT-ICR-MS measurement methodologies for the analysis of different natural resins, such as dammar resin, shellac resin, colophony, sandarac, and mastic. The development of FT-ICR-MS methods includes the use of different ionisation sources (MALDI, APCI and ESI), introduction of novel positive and negative ion mode internal calibration standards, exploring new matrix materials , and testing the capabilities of the known matrix materials in order to gain the maximum amount of high quality data from such complex material. Currently, the work continues to extend and improve the measurement methodologies for the analysis of resinous materials and archaeological lipids with MALDI-FT-ICR-MS using innovative features: use of positive as well as negative ion spectra; direct (without dissolution) analysis of materials; discovery and testing novel matrix and calibration compounds.

Textile dyes and paint binders

In recent years we have expanded our research field to the analysis of textile dyes and paint binder materials. Main objectives are to develop a set of methodologies using complementary techniques – FT-ICR-MS with ESI, APCI and MALDI sources, LC-QQQ-MS, GC-MS, LA-ICP-MS, SEM-EDS, ATR-FT-IR, etc. – for thoroughgoing investigation of the composition of textiles and dyes, as well (semi)quantitative investigation of the composition of one- (oils, proteins, etc) or two-binder systems (oil-protein, oil-wax, etc) in the paint mixtures.

Collaboration

We have good collaboration with the following Estonian museums, conservation centers, and archives: Art Museum of Estonia, Estonian National Museum, Conservation and Digitization Centre Kanut, the National Archives of Estonia. They have been helping us with know-how and providing real-life samples. We have participated in altogether about 50 different projects or contracts with 20 conservation organizations and museums from Estonia and abroad.

 

Currently running comprehensive research projects:

  • Signe Vahur’s Personal Research Funding (PUT1521) “Quantitative instrumental analysis of historical painting materials (1.01.2017−31.12.2020)”.
  • Technical art history research project (2016–2020) „Christian Ackermann – Tallinn’s Phidias, arrogant and talented”. This is a grandiose collaboration research project with Art Museum of Estonia and with Estonian Academy of Arts. In this project, sixteen different cultural heritage objects (altars, pulpits, coat of arms, sculptures etc) from the city and country churches located in various parts of Estonian will be investigated.

Past research projects we participated in:

Award by Estonian Research Council for popularizing science

List of publications