We’re delighted to share that members of our Archemy and Analysis of Cultural Heritage Objects groups have published a new article titled, “Influence of Mineral Composition and Firing Temperature on the Micro- and Mesoporosity of Replicate Archaeological Ceramics” in the journal of Clays and Clay Minerals (Volume 72, 2024, e13). Read the Open Access article here.
This study examines how the mineral composition of clay and temper, along with firing temperatures, influences the formation of micro- and mesopores in pottery. The porosity of ceramics is considered a significant factor in the absorption and preservation of organic compounds, such as lipids, within archaeological pottery. Our research provides the first quantitative analysis of pore structures in ceramics designed to replicate archaeological samples, establishing valuable baseline information for future investigations into ceramic porosity and organic residue analysis.
On the 5th of September 2024, PRG workgroup members Dr Signe Vahur, Dr Anu Teearu-Ojakäär, Dr Rünno Lõhmus, Dr Aleksei Treštšalov and specialist MSc student Martin Leissoo visited the Mitutoyo metrology lab at Riga Technical University (RTU) where the director of the lab Ass. Prof. Janis Lungevics kindly hosted them and introduced different new equipment in the lab.
From left: Rünno, Aleksei, Janis, Signe, Martin, and Anu
The one-day trip was undertaken for the purpose of research work. As part of the collaboration, various materials related to the PRG project have been measured with an optical 3D profilometer in Mitutoyo’s laboratory. Janis introduced the 3D profilometer and showed also very interesting research results that will be published in the joint scientific article.
All the members of the PRG group were very excited about the visit, which gave new interesting ideas for further research.
Thank you, Janis, for a very interesting day and all the support and help!
Janis demonstrating the power of the 3D profilometer
We are delighted to announce that the prestigious ERC Starting Grant was awarded to a member of our group and head of the Archemy team – Associate Professor in Analytical Chemistry and Archaeology Ester Oras!
Ester Oras. Photo: Andres Tennus
The European Research Council (ERC) Starting Grant is awarded to early-stage researchers to carry out their outstanding ideas over the next five years. Ester’s project aims to explore our distant ancestor’s identities through diet by conducting biomolecular analysis on at least 150 burial finds, uncovering details of life from a thousand years ago.
Food is a crucial element in understanding identity, revealing details about social roles, status, and even how the person spent their childhood. By examining bones, teeth, and food residues from pottery, the team can reconstruct how a person’s diet evolved over their lifetime. This will help answer questions like whether an individual ate foods typical of their gender or social class and if they grew up in the area where they were buried.
During the project, various burial finds will be analysed, focusing primarily on sites in Estonia from the years 1000–1400. Using advanced techniques, the team will analyse various molecules, including fats, proteins, and DNA, to uncover specific details about what ancient people ate. This comprehensive approach could even identify not only if the person ate fish but also whether it was cod or herring, offering a deeper look into the lives of our ancestors.
What makes this research groundbreaking is its combination of modern scientific methods with traditional archaeology. Machine learning will be used to integrate the results from various analyses, helping to identify connections between individuals and communities. The project marks a significant step forward for archaeological research, offering new perspectives on ancient identities and social structures.
We are excited to share our latest publication titled, “pKaH values and θH angles of phosphanes to predict their electronic and steric parameters” (Dalton Trans., 2024, 53, 14226-14236. https://dx.doi.org/10.1039/d4dt01430h).
In this study, we delve into the fascinating world of phosphanes – a versatile class of organic bases that play a crucial role in a wide array of chemical applications. Phosphanes are known for their incredibly diverse range of basicities, with pKaH values spanning over 30 orders of magnitude. One of the key insights from our research is that pKaH values can be a valuable alternative to Tolman electronic parameters (TEP values) for assessing the electronic properties of phosphanes. This finding opens up new possibilities for researchers to evaluate phosphanes without the need for the time-consuming preparation or calculation of metal-ligand complexes.
In addition to electronic properties, we also propose new geometric parameters to assess the steric properties of phosphanes – the θH angles, which have the advantage of being accessible by simple computations. Together, the pKa values and θH angles provide a straightforward approach to understand and predict the behavior of phosphanes in various chemical environments and processes.
Our study combines computational and experimental findings to offer a fresh perspective on how phosphanes can be analyzed and utilized, and we believe it will be a valuable resource for researchers working with these compounds. We invite you to read the full article to explore the detailed findings and implications of our work.
From June 2 to June 6, 2024, Signe Vahur and Anu Teearu-Ojakäär attended the 72nd ASMS conference on mass spectrometry and allied topics at Anaheim Convention Center (Anaheim, USA).
Signe and Anu at ASMS
This year, the conference hosted almost 6800 attendees and 183 companies. During the four days there were 384 oral presentations that ran in 8 parallel sessions and 3288 poster presentations (more than 800 posters per day) on wide variety of topics related to mass spectrometry – developments in instrumentation, analysis of complex and problematic samples, using AI and software solutions to improve measurements, data handling, etc. In addition, there were 50 evening workshops and 49 breakfast seminars. From Monday to Wednesday evening, 15 daily corporate hospitality suits were hosted by some of the companies (e.g., Bruker, Agilent Technologies, Shimadzu, Thermo Scientific, etc.).
Anu and Signe in front of their poster
At the conference, Signe and Anu presented their poster “APCI-MS for the analysis of cultural heritage materials” during the Thursday (June 6) poster session. On Monday evening (June 3), Anu gave a 3-minute Flash talk at the evening workshop “Art, Museums, and Archaeology” for an audience of approximately 160 attendees.
Anu giving a Flash presentation
The 72nd ASMS conference was a great experience by meeting old colleagues and fellow MS enthusiasts, making new connections, having great and fruitful discussions and networking opportunities. Thank you to the organisers of the conference for delivering yet another high-level event!
At the beginning of the presentation, Ivo gave a brief overview of why pH, a widely used value for expressing acidity, has serious limitations. Thus, it cannot be used to compare the acidities of solutions in different solvents, which can hinder the understanding of chemical, biological, environmental, and industrial processes.
A much more practical approach could be the usage of an absolute/universal pH, which would allow the comparison of acidities in different solvents. Thus, the main part of the presentation was focused on the theoretical and practical aspects of unified pH (pHabs). In recent years, our Acid-base Studies workgroup in the Analytical Chemistry Chair has worked extensively with the development and measurement of unified pH values for various systems in different solvents (liquid chromatography modile phases, electrocatalytic mixtures, strongly acidic solutions, etc). A differential potentiometry method for pHabs has been developed in the workgroup to obtain the unified pH values and has been now distributed to a number of groups in Europe in the framework of the UnipHied project.
For now, the unified pH has matured from a concept into a practical tool and has been accepted both by the European metrology community (Euramet) and by IUPAC. The unified pH could be utilized in various applications, such as liquid chromatography, catalytic systems, and acidity at the interfaces between phases.
The presented research is largely the result of the EMPIR programme project 17FUN09 “UnipHied”.
We are happy to announce that Mari Tõrv, Research Fellow in Analytical and Physical Chemistry and Associate Professor of Archaeology at the University of Tartu, was awarded the Professor Peeter Tulviste Memorial Fund scholarship.
Rector Toomas Asser and Dr. Mari Tõrv (photo: Andres Tennus)
Her interdisciplinary research combines archaeological heritage and analytical chemistry to gain insight into people’s past habits and practices. By applying both – humanities and natural sciences – she has improved our knowledge on human diet, diseases, and even funeral rites.
Besides research, she has been part of creating an infrastructure for preserving archaeological heritage digitally, founding the Estonian Association of Archaeologists, and developing the webpage eestijuured.ee to gather and promote the research about the ethnic history of Estonia during the last 11,000 years from the first hunter-gatherers to the digital nomads that we are today.
For Mari, the scholarship was a great recognition. “The scholarship proves that understanding cultural heritage is important in today’s crisis-torn world because it is the basis of our common identity.” She plans to use this scholarship to research further the culture of death by bringing together the analytical tools from biomolecular archaeology and social theory.
Mari obtained her PhD in archaeology in 2016 with joint supervision from the University of Tartu and the Christian-Albrecht University of Kiel. Since 2017, she has led the Collegium for Transdisciplinary Studies in Archaeology, Genetics, and Linguistics at the University of Tartu. In the Chair of Analytical Chemistry, she is part of the Archemy research group, where her expertise lays on stable isotope analysis of human and animal tissues.
During recent years, we have been engaged in extensive investigations of the unified pH (pHabs) values of reversed-phase liquid chromatography (RPLC) mobile phases. The pHabs scale has the advantage over the conventional pH scale because pHabs values express acidity in terms of the thermodynamic activity of the solvated proton. Therefore, pHabs values are directly comparable between solvents/media of different compositions. At the same time, pHabs is convenient to use, as pHabs values of aqueous solutions are equal to the respective conventional pH values.
This comparability is especially useful in RPLC, as mobile phases are mixtures of water with organic solvents in different ratios. Thus, it can be said that pHabs is the best way of expressing pH if a rigorous comparison of pH between solutions in different solvents is needed.
The ΔpHabs values were measured by differential potentiometry, using potential differences in a symmetric cell with two glass electrode half-cells (see figure above) and almost ideal ionic liquid triethylamylammonium bis((trifluoromethyl)sulfonyl)imide [N2225][NTf2] salt bridge with multiple overlapping measurements. The system of altogether 300 ΔpH values, pictured in the “ladder” scheme below, was anchored to the pH value of standard pH 7.00 aqueous buffer solution.
In addition, a simpler measurement method that uses double junction reference or double junction combined electrodes was tested and was found suitable for routine laboratories. The results show that the design of the junction is an important factor in deciding if the electrode can be used for unified acidity measurements. This is the first successful use of double junction combined electrodes filled with ionic liquid for the measurement of pHabs values.
The Institute of Chemistry received an award for its consistent and systematic efforts over the past three years to improve the quality of education.
One of the main goals was to develop students’ skills in specific subjects by changing teaching methods and involving students more actively in learning. For that, seminars were organized together with the teachers, which led to the realization that also the subjects of the lectures needed to be adjusted and coordinated with each other. Student feedback was used to improve courses, and the online learning platforms were updated. In parallel, the entire curriculum was revised.
Chemistry Master program director Edith Viirlaid and Vice-Rector Aune Valk
According to the Vice-Rector Aune Valk, the award recognized the Institute’s systematic and integrative approach to improving the quality of education. She emphasized the importance of consistent work for keeping the students engaged by active learning and motivating the students by making education more interactive and relevant to future careers. She also highlighted that there has already been a positive response from the students who appreciated the improvements.
In the University of Tartu, the award for improving the quality of education acknowledges a university institute, college, or department for their successful planning and implementation of activities that enhance the quality of learning. It is important that these initiatives include the collaboration between the faculty and students. Here is the original post in Estonian.
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.
