The analytical chemistry scientists (Dr Signe Vahur, Dr Anu Teearu-Ojakäär, Prof Ivo Leito) together with physicists (Dr Rünno Lõhmus, Dr Aleksei Treshchalov, Prof Jaak Kikas) from the Institute of Physics at the University of Tartu and conservation scientists at the Estonian Academy of Arts (Prof Hilkka Hiiop, MSc Käthi Niman), have published a new tutorial review article, “Laser-based analytical techniques in cultural heritage science – Tutorial review“ in the journal of Analytica Chimica Acta. The article is available here: https://doi.org/10.1016/j.aca.2023.342107.
Graphical abstract in the journal of Analytica Chimica Acta (https://doi.org/10.1016/j.aca.2023.342107)
This comprehensive collaboration article is significant for the cultural heritage investigation workgroup and the PRG1198 project team, which is currently developing a new laser-based MS system.
The main focus of this tutorial review is to give a simple and accessible overview of the physical background of different lasers, their parameters, and examples of applications in analytical techniques useful for the identification of components of various complex materials from a cultural heritage point of view. Besides conservators and cultural heritage scientists, this review may also interest researchers and students of other fields (e.g., material science, physics, chemistry, forensics, etc.) who wish to know more about lasers.
During June 4-8, 2023, Signe Vahur and Anu Teearu-Ojakäär attended the 71st ASMS Conference on Mass Spectrometry and Allied Topics, held in Houston, USA.
Signe and Anu presenting their poster
At the ASMS conference, Signe and Anu presented their poster “MALDI-MS for the analysis of cultural heritage materials” during the Monday (June 5) poster session.
On Wednesday evening (June 7), Signe was an invited panelist (along with Dr G. Asher Newsome from Smithsonian Museum Conservation Institute, USA; Prof Paul Haynes from Macquarie University, Australia; Dr Aleksandra Popowich from the Metropolitan Museum of Art, USA; Assoc Prof Enrico Cappellini from University of Copenhagen, Denmark; and Assoc Prof Troy Wood from University of Buffalo, USA) in the workshop “Art, Museums, and Archaeology” and had a very interesting discussion with approximately 70 attendees.
Altogether, the ASMS 2023 conference had more than 6300 attendees from all over the World. During four days there were 384 oral presentations (that ran in 8 parallel panels) and 4 presentations by invited speakers; 2939 poster presentations (more than 700 posters per day) and 178 corporate members presenting their products – instruments, labware, sample preparation, software solutions, etc. In addition, there were 50 evening workshops, 49 breakfast seminars, and 16 daily corporate hospitality suits.
All in all, the 71st ASMS Conference was a great experience with a lot of new connections, great discussions, and networking opportunities. Thank you to the organisers of the 71st ASMS Conference for delivering such a high-level event!
Signe talking during the panel sessionSigne in the main conference hall
From the 28th of June to the 1st of July 2022, Dr Signe Vahur, Dr Anu Teearu-Ojakäär from our UT Analytical Chemistry Cultural Heritage Investigation group, and PhD student Shidong Chen from the Archemy group attended the 5th international inArt2022 conference in Paris, France.
Anu, Shidong, and Signe
InArt is a conference where professionals from different disciplines (for example, chemistry, archaeology, conservation, biology, etc.) can present and discuss the analysis results using a limited amount of samples or non-invasive approaches and conservation strategies of cultural heritage objects. The conference included altogether 47 oral presentations and three poster sessions with 135 posters, different visit options (starting with the National Centre for Research and Restoration in French Museums (C2RMF) to a walking tour in the historical centre of Paris), and dinner at the hotel The Westin Paris.
Investigations from Fayum mummy portraits to street art
Four days were filled with a wide range of interesting presentations, from hyperspectral imaging and material instrumental analysis of different cultural heritage (paintings, sculptures, manuscripts, etc.) and archaeological objects to investigations of chemical and physical degradation mechanisms of various materials.
Some of the most interesting talks included the presentation by Prof Francesca Modugno (from the University of Pisa) about the SuPerStAr project dedicated to the studying and preservation of street art and Dr Lucile Brunel-Duverger (from French Museums Research and Restoration Center) about the analysis of madder lake dyes in the Fayum portraits (from 1st to 4th century A.D). Also should be highlighted the presentations by Dr Maria Filomena Guerra (from French Museums Research and Restoration Center) on the analysis of objects covered with gold leaf and foil from the Egyptian Middle Kindom period, Dr Laura Pagnin (from the Polytechnic University of Milan) about data fusion of Py-GC-MS and FT-IR data to determine degradation in modern paints, and also Loïc Forma (from The National Heritage Institute in Paris) who talked about how to protect cultural heritage objects from vibrational damages. There were many eye-catching poster presentations, however worth mentioning is the poster made by Dr Louise Chassouant and her colleagues on the chemical and palaeobotanical study of Roman amphorae. In their research, they developed a multidisciplinary approach (applied in archaeometry techniques) to analyse the original content of the amphorae (e.g. components of wine, oils, etc.) and determine the waterproof resin coating components in the internal surface.
The highlights of our recent results
Signe presenting her poster
Anu presenting her poster
Shidong presenting his poster
At the inArt2022 conference, we had three poster presentations from which we could present our research topics and results. Signe presented her poster “Quantitative mineralogical analysis of clay-containing materials using ATR-FT-IR-PLS method”, where an easy and quick quantitative method for determining the mineralogical composition of clays in different sizes and amounts of cultural heritage (i.e. pottery, sculptures, construction materials, etc.) samples using ATR-FT-IR spectroscopy with partial least squares (PLS) analysis is presented. Anu presented her poster „ Analysis of Early Modern Age medicine found in a shipwreck from the Baltic Sea“. In this study, ATR-FT-IR, pyGC-MS, and MALDI-FT-ICR-MS techniques were combined to determine the chemical composition of materials (like pine tar, essential oil, etc.) in the pharmacy jar found on a 16th-century shipwreck in the Baltic Sea. Shidong presented his poster “Classification of Archaeological Adhesives from Eastern Europe and Urals by ATR-FT-IR Spectroscopy and Chemometric Analysis”. This study showed that ATR-FT-IR-DA classification is a rapid and reliable pre-scanning method for analyzing archaeological adhesives (e.g. birch bark tar), which is especially suitable for small samples.
Overall, the inArt2022 conference gave our cultural heritage and archaeology objects researchers the possibility to introduce their scientific work results, hear presentations of investigation of different materials, obtain valuable tips for further research and have interesting discussions with other scientists.
Yesterday, on November 18, 2021, Dr. Signe Vahur made a presentation about our cultural heritage investigation workgroup at the Annual Conference of the University of Tartu Museum called “100 years of Tullio Ilomets”.
This summer (July 13, 2021) would have been the 100th birthday of the legendary chemist, scientific historian, and cultural heritage protector and investigator docent Tullio Ilomets. This conference was dedicated to him, and different people who worked with him, were his students or were influenced by him made presentations. Dr. Signe Vahur was his student and thanks to his motivation and influence, we now have our cultural heritage workgroup.
The conference can be watched from here (it is in Estonian).
Additionally, small samples from two paint case study samples relevant to the history of Estonia – crucifix from Karja church and cupboard from Ruhnu island – were analyzed to obtain information about the materials in the paint samples. Finally, the improved quantitative method was used to quantify fatty acids present in yeast cells.
Yesterday, on the 7th of May, Associate Professor emeritus of physics Matti Laan gave a highly interdisciplinary lecture about laser cleaning in the field of cultural heritage.
On this project, Dr. Laan (presenting his lecture in the picture on the right) worked with the late Associate Professor emeritus of chemistry Tullio Ilomets. Dr. Laan gave an exciting lecture about different lasers (e.g., Nd:YAG, XeCl, Er:YAG) and which of them is most suitable for laser cleaning of various artefacts (such as paintings or sculptures). For this laser ablation is used, which removes any undesired material (including ageing products and materials from previous conservation works) layer by layer.
Most of the listeners participated via the Zoom platform – over 70 physics, chemists, conservators, material scientists, and people from other disciplines joined in this interdisciplinarity lecture. The lecture was organised by our Cultural Heritage workgroup, Institute of Physics, and The Estonian Academy of Arts in the framework of Dr. Signe Vahur’s PRG1198. The recording (in Estonian) can be found here.
In this freely accessible publication, seven sets of artificially aged paints prepared from a pigment (chrome oxide green, natural cinnabar, Prussian blue, red ochre, hematite + kaolinite, zinc white, or yellow ochre) and linseed oil were analysed with GC-MS. One of the main aims was to study if the pigment concentration in the paint samples affects the drying of the linseed oil.
The palmitic acid to stearic acid ratio (P/S), azelaic acid to palmitic acid (A/P), and the relative content of dicarboxylic acids (∑D) showed, that besides the type of the pigment, also the concentration of the pigment can influence these values that are commonly used to identify the type of the oil or to characterize how dried is the sample.
The absolute quantification of stearic acid (see figure on the right) showed that the drying of all paint sets (except for zinc white) were influenced by the pigment concentration. Therefore, this is another factor that needs to be taken into account when studying aged oil paints.
This year the Estonian Research Council has presented 49 female Estonian scientists to the AcademiaNet database. From the Unversity of Tartu, seven names were given, including Dr Signe Vahur (on the picture), a research fellow in our Chair of Analytical Chemistry.
The AcademiaNet contains profiles of excellent female researchers from all disciplines. The database enables wider recognition worldwide, allowing scientists and research institutions to search for suitable collaborations, experts, or speakers. The database was initiated in 2010 and, by now, has the profiles of 3000 outstanding female researchers from all over the world.
Since 2003, Dr Signe Vahur has done research in the field of conservation science and specialized in the investigation of cultural heritage objects (paints, textiles, paper, resinous materials, etc.) with a vast collection of instrumental techniques. She has also worked as a conservator of polychrome objects and now is the leader of our Cultural Heritage workgroup. Recently, her team started to develop a new device that could be used to analyze valuable cultural heritage objects, so there’s only more to come!
9-aminoacridine (9-AA) is a well-known matrix material used for the MALD(-)-MS analysis. Among the other monoaminoacridines (AAs), only 3-AA has been tested once (in our cultural heritage workgroup) but the suitability of the other AAs was unknown.
To fill this gap, the capabilities of all five AAs were studied by analysing different materials (stearic acid, colophony resin, dyer’s madder, and a resinous sample from a 16th-century shipwreck). Also, a vast range of properties for these aminoacridines were experimentally or computationally characterized (including UV-Vis absorption and fluorescence spectra, proton transfer reactions, crystallization).
The results demonstrated, that all the AAs are suitable for the MALDI(-)-MS analysis of these materials. Interestingly, 3-AA and 4-AA outperformed the other AAs (including the best-known 9-AA) and were the preferred matrices for the analysis of samples studied in this work.
We are happy to announce that Dr. Signe Vahur’s Personal Research Funding Team grant (PRG) project got funded!
Yesterday, on the 5th of January was the first meeting with the team members of her new PRG project. The main aim of this project is the development of a new MS system for the analysis of cultural heritage objects. This project is highly interdisciplinary, as it brings together researchers from natural sciences (analytical chemistry, physics, engineering) and humanities (conservation science, art history, archaeology). The duration of this project is 5 years.
We will keep you posted with new developments of this very demanding and interesting project!
