Eliise Tammekivi, Author at Chair of Analytical Chemistry

A new article about a developed laser ablation-based mass spectrometric system for the analysis of cultural heritage materials has now been published!

The Cultural Heritage research group, as part of this year-end PRG1198 research project, has published an open-access article titled “Laser ablation APCI-HRMS method for the analysis of cultural heritage materials” by Anu Teearu, Martin Leissoo, Rynno Lohmus, Alexey Treshchalov, Tõiv Haljasorg, Victor Augusto Xavier da Silveira, Hilkka Hiiop, and Signe Vahur in the Journal of the American Society for Mass Spectrometry. The article is available here.

This research article highlights a novel 355 nm optical fibre-coupled laser ablation (LA)-APCI-FT-ICR-MS system, developed for direct, controllable, rapid, and accurate analysis of organic materials from the solid surface of an artefact under ambient conditions with minimal surface damage and without the need for sample removal or sample preparation for the analysis. In this study, the effectiveness and capabilities of the developed LA-APCI-HRMS system for analysing five aged mock-up materials (copper resinate, Prussian blue oil and egg tempera paints, lead white oil paint and matte dammar varnish) and the blackish-brown material from an ointment jar from a 16th-century shipwreck were investigated. The results can be read in the article.

The PRG1198 project team has done excellent work over the past five years, culminating in a working laser-based HRMS system. The same team will begin next year with a new project, and we will continue to keep you updated on all new developments.

In the photo, the main members of the PRG team: team leader Dr Signe Vahur (in the centre), from left Dr Aleksei Treshchalov, Prof. Hilkka Hiiop, Dr Anu Teearu-Ojakäär, Dr Rünno Lõhmus and specialist Martin Leissoo.

Our LC-MS validation activities at the IUPAC-DSM LC-MS validation workshop

Riin Rebane, Asko Laaniste and Ivo Leito participated on 10-11.12.2025 in the Joint IUPAC-DSM Workshop on LC-MS method validation and performance, organised jointly by the IUPAC’s Division of Analytical Chemistry and the Mass spectrometry division (DSM) of the Italian Chemical Society.

Riin presented the opening keynote of the event titled “Principles of method validation”. Her presentation reframed LC-MS method validation as a risk-management process rather than a checklist of validation characteristics. By zooming out to the method’s intended purpose, each validation characteristic is linked to the specific risks it is designed to control. This view allows to build evidence that the method performs reliably under real-world conditions and is truly fit for purpose and produces results with known confidence.

Ivo’s talk “What are the issues encountered in the real world? Lessons learned form an online validation course” presented an analysis of the main issues brought up by the participants of the nine editions of an online LC-MS method validation course (https://sisu.ut.ee/lcms_method_validation/). The analysis of 2640 course forum posts and 336 participant feedback submissions revealed that practitioners struggle a lot with calculations and spreadsheet software, which diverts effort from real “analytical hemistry” issues.

Asko’s session “ValChrom open-access online validation software” was a workshop in the true sense of the word: a hands-on session on the online validation software ValChrom developed at UT. Participants had instant access to the software freely available in web and demo materials. Asko walked them through the whole process of ValChrom from start to finish, from defining analytes to customizing experimental plan with AI and finishing with automatically generated DOCX file with the whole validation data in it. ValChrom’s Design of Experiements (DoE) capabilities were also covered and it was nice to see that throughout the two days a big number of presentations also involved DoE one way or another, indicating a rising need for such tools.

All in all, the contributions of our team were highly appreciated, indicated by numerous questions, both during sessions and (especially) during coffee breaks.

This year’s recipients of honorary decorations have been announced

Ivo Leito and Koit Herodes were awarded honorary decorations by the University of Tartu.
Professor Ivo Leito received the University of Tartu Grand Medal, and Associate Professor Koit Herodes received the University of Tartu Badge of Distinction.

Ivo, our Professor of Analytical Chemistry, has been recognised with the university’s highest internal honour for services of particular value. The Grand Medal highlights Ivo’s internationally renowned scholarship that blends high-level fundamental research with metrological precision and innovative teaching. His excellent leadership and mentorship have shaped generations of chemists and strengthened the standing of analytical chemistry at the University of Tartu and beyond.

Koit, our Associate Professor of Analytical Chemistry, has been awarded the University of Tartu Badge of Distinction in acknowledgement of his dedicated service to the University. Koit’s contributions to analytical chemistry spanning from research to teaching have had a strong positive impact on our group’s scientific excellence and student experience.

The decisions were made by the University of Tartu senate on October 31. The University will present this year’s honorary decorations at a ceremony on 21 November at 16:00 in the University of Tartu assembly hall. More information and the other recipients can be found here.

Please join us in congratulating Ivo and Koit on these well-deserved recognitions!

ICNTS25 – Gathering people without targets!

Having no predefined targets in your sample isn’t always a drawback. The International Conference on Non-Targeted Screening (ICNTS) demonstrated how omitting targets in mass spectrometry analysis can reveal a broader and more nuanced picture of the chemical space.

From October 13-16, for the fifth time, non-targeted screening experts from around the world gathered in Erding, Germany, to share their latest research and exchange ideas. The event showcased cutting-edge developments across diverse fields, including metabolomics, foodomics, water analysis, harmonisation, and prioritisation.

Representing our group, Pilleriin Peets, Principal Investigator of the Chemical Space & Omics group, gave an oral presentation on compound class vectors for comparing metabolomics samples. Her talk was part of the computational mass spectrometry session, chaired by Emma Schymanski, who also gave a keynote on “Data Handling in a Modern NTS World.”

The ICNTS once again proved that by embracing the unknown, researchers are expanding the boundaries of chemical analysis and opening new doors for discovery. Whether in environmental science, health, or food safety, the power of non-targeted approaches lies in their ability to reveal what we didn’t even know to look for.

Learn more about the conference and the community: https://afin-ts.de/icnts25/

Indrek Saar, PhD

On the 27th of August, Indrek Saar successfully defended his great innovation-based dissertation „Development of novel on-site chemical analysis tests – from alternative materials and technologies to functional prototypes”.

With his opponent Prof. Nicole Pamme, who is focused on Lab-on-a-Chip devices, they gave a memorable and enjoyable PhD defence at the Institute of Chemistry. Prof. Nicole Pamme holds a chair in Analytical Chemistry at Stockholm University. During the defence, her excellent general science-to-market questions, as well as detailed questions specific to chemistry and material science, helped the audience to gain a clear understanding of the need for research, practical applications and how everything was also achievable from a technological perspective.

Indrek’s dissertation has given valuable new insights into the simple to use on-site chemical analysis tests.

Picture of the fully assembled Biotin test developed in this work.

What if advanced chemical testing could be done anywhere – right where the need arises, without a laboratory?

Traditional high-quality chemical analyses often require complex equipment, trained personnel, and significant time, creating a need for faster, more accessible solutions. In Indrek`s thesis, new on-site chemical analysis tests were developed that not only simplify testing but also aim to achieve higher analytical performance than existing portable methods. These tests were developed using a novel screen-printed particle-based method that is fast, low-cost, and potentially scalable for mass production.

The applications of functional prototypes included monitoring biotin levels in urine and measuring different metal cations in various water samples, even in challenging agricultural nutrient solutions containing strong chelating agents.

Separation of biotin and its metabolites on the printed microfluidics chip. The chip has been visualised by spraying it with a solution of p-dimethylaminocinnamaldehyde (p-DACA) in ethanol and sulphuric acid.

These patented innovations are laying the foundation for highly capable, mass-producible diagnostic tools that can enable faster, more accurate decision-making in environmental monitoring, healthcare, and agriculture.

During his PhD studies and research, Indrek was supervised by Dr Hanno Evard and by Prof. Ivo Leito. Indrek’s special thanks go to the main supervisor, Dr Hanno Evard, who had been a constant source of guidance, encouragement, and support. From countless discussions and brainstorming sessions to planning and problem-solving, Hanno’s insight and commitment had been central to this work.

A Smooth and Memorable Defence

On the 27th of August, Marta-Lisette successfully defended her dissertation “Exploring the basicity of phosphanes and related compounds”, marking an important milestone in her academic journey. Her dissertation has given valuable new insights into the basicity and preparation of phosphanes and related compounds. The defence was conducted in an atmosphere of professionalism and collegiality, with a thoughtful exchange of ideas and perspectives.

Special thanks go to the opponent, Dr Martin Smith from Loughborough University, whose insightful and well-chosen questions guided the discussion. His role helped ensure the defence was not only rigorous but also smooth and engaging.

It was a proud moment for Marta (and her supervisors) and a wonderful occasion for everyone who has supported her throughout this process. Congratulations to her on this achievement!

Publication: Derivatization for success

Recently, a tutorial review was published in Analytica Chimica Acta by Riin Rebane and Ivo Leito, named Derivatization for success: a tutorial review of liquid chromatography mass spectrometry method optimization for determining amino compounds. Read next what Riin has to say about the review.

“This comprehensive review brings together technical depth and years of personal lab experience, shaped by long hours at the bench, countless peer discussions, and valuable lessons learned along the way. It offers a detailed, practice-oriented guide to how derivatization can dramatically improve analyte retention and ionization in LC-MS, especially for challenging amino compounds. The article dives into reagent selection, method optimization, and real-world troubleshooting – tools I wish I’d had starting out.”

This work was supported by the Estonian Research Council grant PUT1589, and by the Estonian Ministry of Education and Research (TK210). The research was conducted using the Estonian Center of Analytical Chemistry, funded by the Estonian Research Council (TT4).

Graphical abstract for the tutorial review

Paleoproteomics course by visiting Professor Matthew Collins

Prof. Collins (left) with the students demonstrating the working principles of mass spectrometry

From the 17th to the 21st of March, the Archemy group welcomed Professor Matthew Collins, a Professor of Paleoproteomics at University of Cambridge and the University of Copenhagen, at University of Tartu for a week-long paleoproteomics course.

The course, attended by students and researchers from University of Tartu and the Collège de France, covered the fundamentals, methods, and applications of ancient proteomic studies using both MALDI-TOF mass spectrometry and LC-MS/MS.

Since the attendees’ backgrounds varied from archaeologists to chemists and geneticists, the course began with a review of the fundamentals of organic chemistry. Masterfully, Prof. Collins continued with an introduction to mass spectrometry and a method called ZooMS – zooarchaeology by mass spectrometry, which is based on detecting marker peptides to determine animal taxonomy.

The course continued with an intensive introduction to analyzing the paleoproteome using LC-MS/MS and the opportunities it provides in analyzing ancient ways of life, for example, determining the species used for dairy production. However, the shortcomings of the methods were also discussed. In archaeological material, the most prevailing issues tend to be contamination with modern and more abundant proteins, as well as the deamination of amino acids due to their advanced age. Despite the difficulties in analyzing ancient proteomes, the debates on the final day still concluded that the methods are highly applicable in archaeological studies.

Prof. Matthew Collins led the intensive course within the project PaleoMIX: Nurturing Heritage Science with Novel Bioarchaeological Methods in the Eastern Baltics, PI Mari Tõrv (UT). Project partners include the University of Copenhagen, the University of Burgos, and the University of York.

Read more about paleoproteomics and its applications in an interview with Prof. Collins (in Estonian).

Unified and comparable quantification of catalytic activity of Brønsted acids is now possible!

Our group’s journey into catalytic studies began years ago. In the first period our main activity was measuring the pKa values of Brønsted acids catalysts and relating them with catalytic activity. However, it was always problematic that the catalytic activity was quantified by different authors in very different ways: different reactions, different substrates of the same reaction, different ways to express activity (rate constant, yield), different solvents, different concentrations, different temperatures… All this diversity makes comparing catalytic activity difficult to impossible.

So, we set forth to find a model reaction, define conditions and a unified quantitative parameter for expressing acatlytic activity of various Brønsted acid catalysts.

This endeavour has now reached its first result: PhD student gleb Maksimov from our group discovered that the transfer hydrogenation reaction with substituted quinoline has the suitable characteristics for this work and utilizing the Kimball-Collins theory modelling approach applied to rate constante (measured by NMR), a catalytic activity parameter was defined that enables unified and comparable quantification of the catalytic activity of Brønsted acids! The proof of principle is now published: Molecular Catalysis 2025, 573, 114846. Towards quantifying catalytic activity of homogeneous Brønsted acid catalysts.

Congratulatuons, Gleb!

However, this work is far from complete. Gleb together with new students will continue to improving te methodolog and widening the applicability of the approach so that many more results and with higher quantitative accuracy would be possible in the future. We are excited about the potential advancements and look forward to sharing more updates as the research progresses.

(This research was supported by grant PRG690 from the Estonian Research Council)

Integrating omics – NPLinker workshop in Wageningen

They say it takes a village to raise a child—and in science, it takes a community to push boundaries and do great science. In the multi-omics field, the best discoveries emerge from collaboration among chemists, microbiologists, bioinformaticians, computer scientists, and many others.

The NPLinker community in Wageningen, Netherlands, is dedicated to bridging the gap between genomics and metabolomics while also connecting researchers analyzing these complex datasets.

This week Pilleriin Peets had the fantastic opportunity to once again participate in their five-day intensive hands-on workshop, which covered key tools and applications, including BiG-SCAPE, MZmine, GNPS2, NPLinker, and PairedOmics.

A highlight of the week was the Symposium on March 26, celebrating 10 years of genomics mining and 5 years of metabolomics mining at Wageningen University & Research. Genomics mining research in Wageningen is led by Marnix Medema, whose developments include antiSMASH and MIBiG. Metabolomics topics were covered by Justin J.J. van der Hooft, whose contributions to the field include PairedOmics platform, as well as MS2Query.

The symposium’s keynote was delivered by Pieter Dorrestein, one of the most influential scientists in metabolomics, with over 400 publications and 75,000 citations. His work in computational metabolomics includes the Global Natural Products Social Molecular Networking (GNPS) platform, which enables researchers to find spectral connections within their samples and annotate compounds using publicly available spectra. During his talk, he highlighted his bile acid research and emphasized the critical role of open-access data in advancing the field.

Knowledge from this week will be brought back to Tartu and Pilleriin is eager to integrate GNPS2 into her workflow to enhance compound annotation in her non-targeted mass spectrometry datasets.

Author: Eliise Tammekivi