The Chair of Analytical Chemistry at University of Tartu

First six months on the project: discussions, hands-on experiments, and new team members

The PRG3112 project at the University of Tartu’s Chair of Analytical Chemistry continues to gain momentum as the team works toward developing a portable, automated laser sampling probe for the study of cultural heritage materials.

During the first six months, the group’s activities have been a mix of lively scientific discussion with collaborators and hands-on experimentation and testing.

In March, the group had a discussion with Dr G. Asher Newsome from the Smithsonian Institution (USA) on sample transfer and the development of the transfer line. Dr Newsome – who has contributed to the development of multiple analytical instruments for cultural heritage research – shared valuable insights from his previous work and inspired several new ideas for improving the transfer line design for the laser sampling probe.

We have also welcomed several new team members, further strengthening the team’s expertise.

From left: Martin, Andres, Rünno, and Rady

In June, the project’s newest member, Andres Uueni (who joined in February 2026), visited the group’s testing lab at the University of Tartu, Institute of Chemistry, for the first time. Andres, who works at Archaeovision and the Estonian Academy of Arts and (Tallinn, Estonia) is an expert in multispectral imaging. His expertise brings an important new dimension to the project, particularly in the development and optimisation of visualisation and spatial analysis capabilities for the laser sampling probe.

Throughout this period, our PhD student Rady Jazmin Remigio (working in the group since September 2025), has been actively evaluating the performance of the laser sampling probe. Through systematic experiments, Rady is investigating how the system performs under different conditions and on various materials, helping to define its capabilities and identify areas for further improvement.

Rady working with the developed LA-APCI-MS system

Overall, the project’s first months have been marked by strong collaboration and the integration of new expertise, laying a solid foundation for the continued development of the laser sampling probe.

Metabolomics, science, and connections in South America

While Estonia was celebrating a sunny and warm Jaanipäev, Pilleriin travelled to wintery Argentina to attend the Metabolomics Society Conference and visit research labs in snowy Patagonia.

This year’s Metabolomics Society Conference — already the 22nd in the series — was held for the first time in South America, in the beautiful city of Buenos Aires. The conference is one of the key events in the field and brings together around 500 participants. Over four days, the programme featured inspiring presentations from society members, early-career researchers, and major sponsors, including Thermo Fisher, Shimadzu, Agilent, Bruker, Sciex, and many others.

Pilleriin also contributed with an oral presentation in the Environmental session, where she introduced her compound class vector method. This approach enables chemically meaningful comparison and characterisation of complex metabolomics datasets.

Before the conference, she travelled to southern Argentina to visit laboratories in Patagonia. At the Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales in San Carlos de Bariloche, research ranges from developing novel yeast strains for the local beer and whisky industry to studying unique lake dynamics at nearby lakes. In addition to learning about their work, Pilleriin gave a presentation to local researchers, opening discussions for future collaborations in metabolomics-related projects.

Next year’s Metabolomics Society Conference will take place in Daegu, South Korea! So if interested, keep an eye on the Metabolomics Society Webpage and LinkedIn.

Keemia bakalaureusetööde kaitsmised 2026

4.-5. mail toimus Chemicumis füüsika, keemia ja materjaliteaduse bakalaureuseõppekava keemia eriala lõputööde kaitsmine. Sel aastal jõudis oma töö eduka kaitsmiseni 16 väga tublit tudengit. Kaitstud tööde teemadering oli lai, ulatudes elektrokeemiast kuni biokeemiani. Kõik lõpetajad olid oma uurimistöösse põhjalikult süvenenud ja käsitlesid aktuaalseid teadusküsimusi.

Tänavused kaitsmised tõid kaasa ka ühe olulise uuenduse – suulise kaitsmise korda muudeti nii, et akadeemilise arutelu osa pikendati 10 minuti võrra. See muudatus võimaldas nii retsensentidel kui ka kaitsmiskomisjonil põhjalikumalt käsitleda tööde tulemusi ning pidada sisukamat teaduslikku arutelu. Heameel on tõdeda, et kõik tudengid tulid selle väljakutsega edukalt toime ja kaitsesid oma lõputööd edukalt.

Kaitsmiskomisjoni hinnangul paistsid tänavu eriliselt silma kaks tudengit, kellest üks (Anni) tegi oma uurimustöö Analüütilise Keemia Õppetoolis:

Anni Romandi ja
Elo Joandi.

Komisjon otsustas nende töid ja kaitsmisi eraldi tunnustada, sest mõlemad lõputööd olid eeskujulikult vormistatud ning nende autorid demonstreerisid suurepärast teemavaldamist ja argumenteerimisoskust.

Anni Romandi uurimistöö keskendus aluselisuse skaala valideerimisele ja täiendamisele atsetonitriilis. Nii teadustööd, tööstuslikke protsesse kui ka keemiasünteesi viiakse rohkesti läbi orgaanilistes lahustites nagu atsetonitriilis, mistõttu on usaldusväärsed aluselisuse ja happelisuse andmed sellistes keskkondades võtmetähtsusega. Töö käigus selgus, et seni kasutatud hapete ja aluste tugevuse skaalade vahel esineb küll väike nihe, kuid see ei mõjuta enamasti nende praktilist kasutamist eelpool mainitud rakendusvaldkondades. Lisaks määrati täpsemad väärtused mitmele väga tugevale fosfaseenalusele, mis aitavad tulevikus usaldusväärsemalt ennustada ainete käitumist erinevates keemilistes protsessides. Töö juhendajad olid PhD Märt Lõkov ja professor Ivo Leito.

Elo Joandi uurimistöö keskendus uudse biosensoripõhise katseplatvormi arendamisele, mis võimaldab uurida serotoniini retseptorite ja nendega seonduvate ühendite vastastikmõju. Töös näidati, et bakuloviiruse nanoosakestel põhinev süsteem võimaldab usaldusväärselt jälgida retseptori aktiivsusega seotud muutusi ning hinnata erinevate keemiliste ainete toimet. Sellised meetodid aitavad paremini mõista närvisüsteemi signaalülekande mehhanisme ning pakuvad uusi võimalusi farmakoloogiliste sõelkatsete läbiviimiseks. Töö juhendajad olid PhD Sergei Kopantšuk ja PhD Santa Veikšina.

Shrikant’s PhD defence – from lignin chemistry to NMR and from uncertainty estimation to water measurement with KF titration and FTIR!

On the 9th of June 2026, Shrikant Shivaji Pawade successfully defended his dissertation Metrological aspects of sampling and water/moisture determination on the example of lignin. As the thesis encompassed a wide range of topics – from lignin chemistry to NMR and from uncertainty estimation to water and moisture content measurement with ATR-FTIR – there were two opponents invited to examine the PhD candidate: Dr. Stephanie Bell (NPL, UK) and Prof. Riina Aav (TalTech, Estonia).

Development of a rapid and non-destructive method for water and moisture content in lignin using ATR-FTIR with PLS calibration

The defence was intensive and entertaining and eventually Shrikant managed to convince the opponents, the defence committee and the listeners that he was on top of the topics that his dissertation embraces. Please accept our warm congratulations, Shrikant!

The dissertation’s main contribution was development of a rapid and non-destructive method for determining water and moisture content in lignin using ATR-FTIR with PLS calibration.

Modelling of temperature-dependent water release to identify suitable evaporation temperatures for oven cKF titration

The method requires a small amount of sample amount and minimal sample preparation. For developing the method, Shrikant prepared a range of calibration and validation samples from lignins of four different origins (two different types of Kraft lignins, Lignova lignin and dealkaline lignin). Water content was determined using vapour-phase coulometric Karl Fischer titration (i.e. oven-cKF titration), supported by modelling of temperature-dependent water release to identify suitable evaporation temperatures. Moisture content was determined gravimetrically using oven drying (at 105 °C, 7 h or 48 h) and lyophilisation (freeze-drying).

Water and moisture content is an important quality characteristic of not only lignin but essentially any natural feedstock. So, it is expected that the results of Shrikant’s thesis will find use in applied bioproducts research, as well as in industrial biorefineries.

Equilibrium Brønsted acidity measurements in 1,2-difluorobenzene

We are pleased to share our latest open-access article titled “Acidity scale in 1,2-difluorobenzene” by John Paulo Samin, Helerin Roomet, Märt Lõkov, Sofja Tshepelevitsh, Jaan Saame, Agnes Heering, and Ivo Leito, published in ACS Omega (DOI: 10.1021/acsomega.6c02089).

In this work, we established equilibrium Brønsted acidity measurements in 1,2-difluorobenzene (1,2-DFB) in terms of pK_a values measured by UV-vis spectrophotometry and unified pH (pH_abs) values measured by differential potentiometry.

The pK_a scale in 1,2-DFB spans 15 orders of magnitude. The pK_a values were determined for 137 acids, 33 of which were directly measured (see Table 1). The remaining values were estimated using correlation equations relating pK_a values in other solvents (acetonitrile and 1,2-dichloroethane) to those in 1,2-DFB. The pK_a scale was anchored to the computational pK_a values of 9 acid compounds.

Furthermore, an experimental unified pH scale spanning more than 10 orders of magnitude was established. The scale was aligned to the aqueous pH scale, assigning pH_abs^H₂O values to the buffer solutions of 22 acids ranging from −0.6 to 10.0 (see Table 2). The potentiometrically measured pH_abs^H₂O values showed good agreement with the values independently calculated from experimental pK_a values anchored to computational reference values, demonstrating the solid foundation of the underlying theory.

These results open the possibilities for quantitatively describing and measuring acid−base processes in 1,2-DFB, including potentiometric and UV−vis spectrophotometric pH_abs^H₂O measurement.

(This research was supported by grant PRG2557 from the Estonian Research Council and TK210 from the Estonian Ministry of Education and Research.)

Visting lecturers – Dr Burcu Binici and Dr Alons Lends

Dr Burcu Binici giving a lecture on metrology

In April, our group hosted two experts who gave lectures on their topics.

First, on April 14-15, Dr Burcu Binici, a specialist at TUBITAK UME (the National Metrology Institute of Türkiye), presented materials on CRMs in the chemistry field to students in the Metrology in Chemistry course. The listeners had the opportunity to broaden their understanding of CRM, RM production, and the requirements for that.

Then, on the weekend of April 17–18, Dr Alons Lends led an intensive NMR course. He is currently working at the Latvian Institute of Organic Synthesis and has extensive experience in various NMR applications. During his course, students and the members of the Analytical Chemistry group learned more about NMR in biomolecular studies and materials science.

Ahmed, a student of the EACH (Excellence in Analytical CHemistry) Master’s program, said about the lectures: “This is what makes EACH special: learning directly from experts. One of the best things about the EACH program is that it brings experts to teach specific parts of your curriculum or to give you a deep dive into fields you already know. That’s what makes you feel very comfortable, as you can get very good answers to your questions from experts.”

9700 Quality-evaluated pKa values of more than 5000 acids in 7 dipolar aprotic solvents!

14.04.2026: The Zenodo data collection (Image on the right)) recently published as IUPAC technical report Acid dissociation constants in selected dipolar non-hydrogen-bond-donor solvents. Pure and Applied Chemistry. 2025, 97, 973, https://doi.org/10.1515/pac-2024-0276 has been updated for the first time by new pK_a values so that its version 1.5.0 now contains more than 9700 quality-evaluated pK_a values of more than 5000 acids in 7 dipolar aprotic solvents (DMSO, MeCN, DMF, pyridine, acetone, propylene carbonate and THF). The values have been collected from around 800 original works. The widest possible selection of compound classes is covered (Table below). The results of this large-scale pK_a data collection and evaluation work are now available for the scientific community to use in reaction mechanism analysis and modelling, catalyst design, computational method development, etc.

Very importantly, the collected pK_a data have been critically evaluated based on predefined quality criteria and depending on situation, kept as they were originally published, flagged as doubtful/unreliable (around 2700 values) or corrected (around 2500 values).

To enable automated processing and data mining, as well as other kinds of cheminformatics, the data are presented as a set of spreadsheets, together with structural codes (SMILES and InChI strings), compound class qualifiers and comments.

The published IUPAC Technical Report contains also comprehensive educational background information on the acid-base processes in non-aqueous media, as well as brief descriptions of the main measurement methods, with focus on the reliability of the data and sources of uncertainty.

The data collection has been deposited in the Zenodo repository and is freely available at https://doi.org/10.5281/zenodo.12608876.

The work has been carried out in the framework of the IUPAC project 2015-020-2-500. It was additionally funded by numerous sources, most importantly the EMPIR programme (project 17FUN09 “UnipHied”, www.uniphied.eu), by the Estonian Research Council grants (PRG690, PRG2557) and by the Estonian Ministry of Education and Research (TK210).

Measurement Uncertainty online course: 797 participants from 96 countries!

On Tuesday, March 24, 2025 the web course Estimation of Measurement Uncertainty in Chemical Analysis was launched the twelfth time as a MOOC (Massive Online Open Course)!Altogether 797 participants from 96 countries are registered! In the map presented above, the yellow color marks the countries from where participants come. True, the map is coarse and some countries are small. Therefore, not all countries are visible. We are very happy that we have 4 participants also from Ukraine this year. Slava Ukraini!
Registration for this run is closed. But good news: if you did not manage to register this time, you are welcome to register for the 2027 edition of the course.

The full course material is accessible from the web page https://sisu.ut.ee/measurement/uncertainty. The course materials include videos, schemes, calculation files and numerous self-tests (among them also full-fledged measurement uncertainty calculation exercises). In order to pass the course, the registered participants have to pass six graded tests and get higher than 50% score from each of them. These tests are available to registered participants via the Moodle e-learning platform.

This course is run under the umbrella of the Estonian Center of Analytical chemistry (https://www.akki.ee/) and forms a part of the Excellence in Analytical Chemistry (https://www.analyticalchemistry.eu/) Erasmus Mundus master’s programme.

LC-MS Validation online course 10th run has finished!

On March 6, 2026 the on-line course (MOOC) LC-MS Method Validation offered by University of Tartu finished successfully.

Eventually, altogether 995 people registered from 95 countries. Roughly half of them, 486 participants, actually started the course (i.e. tried at least one graded test at least once), and out of them, 337 successfully completed the course. The overall completion rate was 34%. The completion rate of participants who started the studies was 69%. The completion rates of active participants (i.e. who started the course) seem to have stabilised at around 60% and have increased during the current run. In any case, there is some food for thought for us on how we could improve the participation rate…

At the same time, those participants who actually took part in the course were very active and asked lots of questions. The questions were often very much to the point and addressed things that are really important to analysts in their everyday work. The course has several forums (general and by topic). During the course period, the overall number of forum posts was around 200 (overall number of posts, both from participants and from teachers), and the forums are still active, and posts are still coming in.

This active participation made teaching this MOOC a great experience also for us, the teachers. The discussion threads gave a lot of added value to the course.

We want to thank all participants for helping to make this course a success!

We plan to repeat this course again in Autumn 2026.

The Cultural Heritage Research Group started with a new PRG project!

In January 2026, the cultural heritage research group – in collaboration with physicists, material scientists, conservators, and IT specialists – launched a challenging new five-year Personal Research Funding Team (PRG) project, led by Dr Signe Vahur. The main goal of the PRG3112 project is to develop a novel, portable, automated laser ablation sampling probe. This tool will enable minimally destructive stratigraphic and imaging analysis of artefacts directly on the object under ambient conditions. In the future, the probe could be coupled with various analytical devices (MS, Py-GC-MS, and FORS) and sampling containers.

We will keep you updated on the progress of this demanding and exciting project!

The research team remains largely the same as in our previous project.