Design, synthesis and application of carbazole macrocycles in anion sensors

Our supramolecular analytical chemistry team has published an article (Beilstein J. Org. Chem. 2020, 16, 1901-1914) about developing carboxylate sensor prototypes that use macrocyclic carbazole receptors as ionophores.

Usually, reported research concludes with the demonstration of binding abilities of receptors and only suggests possible applications at a theoretical level. This work stands out from most publications by incorporating the entire workflow from receptor design to the characterisation of working sensor prototypes.

By involving this additional step, the team demonstrated the shortcoming of evaluating binding with just the receptor and analyte in solution. The predictions of selectivity can change considerably when measuring binding in an actual sensor membrane. This does not mean that such binding measurements would be obsolete, as the issue of binding anions selectively remains relevant in supramolecular chemistry.

The work was published in collaboration with the group of prof. Johan Bobacka at Åbo Akademi. The open access article was published in the Beilstein Journal of Chemistry thematic issue “Molecular Recognition” (in memory of Prof. Carsten Schmuck).

Symmetric Potentiometric Cells for the Measurement of Unified pH Values

Recently the UnipHied consortium published a new article – Symmetric Potentiometric Cells for the Measurement of Unified pH Values. Symmetry 2020, 12, 1150, where we compared the performance of different cells and instruments used to measure acidities on the unified pH scale (pHabs). The advantage of the unified pH scale is that it enables expressing the acidities of any systems – non-aqueous, solutions, colloidal systems, etc – via pHabsH2O values, which are directly comparable to the conventional pH values of the aqueous pH scale.

This is the first time unified acidities have been measured outside of our group. Nine partners from Europe – national metrology institutes and universities – have set up systems to measure pHabs and validated them with standard aqueous buffers.

The results show that the method is robust and does not depend on the cell nor the instrument (pH meter, potentiostat, or electrometer). The inherent symmetry of the cell design helps to reduce the experimental workload and improve the accuracy of the obtained results.

The next step is to measure unified acidities of non-aqueous systems, which could be used by routine laboratories to calibrate their pH electrodes.

The UnipHied project is funded from the EMPIR programme (project 17FUN09) co-financed by the Participating States and from the European Union’s Horizon 2020 research and innovation programme.

A chemist with a Master’s degree in law

A member of our Analytical Chemistry group – Riin Rebane – achieved something rare for a chemist. On the 26th of May, she earned a Master’s degree in law!

Her studies combined both law and chemistry with a focus on intellectual property law. This was also the case for the topic of her Master’s thesis:  Interpretation of patent claims in Europe on the example of chemistry patents.

The aim of the thesis was to investigate how patent claims are interpreted during patent application expertise as well as in courts in the European Union and in the markets important to Europe. After investigating the practices of many countries, Riin concluded that patent claims in patent offices are interpreted quite similarly. However, it was observed from analyzing the practices of national courts that patent claim interpretation in courts is much more inconsistent and causes a lot of uncertainty for patent applicants and owners. For example, it is very likely that a patent approved by the patent offices can be revoked in court or even more confusing, a court in France may revoke, but a German court may not.

Congratulations to you, Riin! We are glad, that your hard work has paid off 😊.

Our LC-MS Method Validation e-course received quality label from HITSA!

Each year the Estonian Information Technology Foundation for Education (HITSA) recognizes the e-courses crested by Estonian educational institutions, that have demonstrated high quality in their online teaching. The main aim of this award is to improve the level of e-courses and to endorse those, that have shown excellence in their teaching.

The awarded quality label certifies the high level of the e-course and recognizes the authors for achieving excellent results in the implementation of e-learning to their teaching process. The importance of e-courses grows year by year. This was especially seen this spring when the majority of teaching and studying had to be done via the web because of the Covid-19 situation. 

This year our LC-MS Method Validation web course was honored to receive the quality label. Altogether 511 people from 77 countries registered to the course last autumn. The LC-MS Method Validation MOOC will start again in autumn 2020.

Congratulations on this well-deserved recognition to Ivo, Anneli, Riin, Maarja-Liisa, Hanno, Koit, Karin, Irja, and Asko from our analytical chemistry group!

Our collection of acidity and basicity data in non-aqueous media has been updated!

The collections of experimental acidity and basicity data in non-aqueous media measured by our group are now up to date on our Chair of Analytical Chemistry webpage. 

Both tables include the compounds name, CAS number and SMILES code. The acidity collection contains 190 compounds, where the compounds available experimentally measured pKa in acetonitrile (MeCN) and pKip in 1,2-dichloroethane (DCE) are given. The pKa in DCE is calculated/estimated based on pKip value. 

The basicity data collection includes 353 compounds and their pKip in tetrahydrofuran (THF) and in DCE. The pKa values in MeCN were re-evaluated taking into account all (close to 700) measurements of 279 bases. Therefore, these pKa values can be considered the most reliable pKa values measured in MeCN available!

Measurement Uncertainty online course: 828 participants from 92 countries!

On Tuesday, March 24, 2020 the web course Estimation of Measurement Uncertainty in Chemical Analysis was launched the seventh time as a MOOC (Massive Online Open Course)!

Currently 828 participants from 92 countries are registered – the largest audience the course has ever had! As was the case in the previous years, the majority of participants are from analytical laboratories. This once again demonstrates the continuing need for training in measurement uncertainty estimation for practicing analytical chemists.

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 measurements and chemical analysis related master programmes at UT: Applied Measurement Science (https://ams.ut.ee/) and Excellence in Analytical Chemistry (https://www.analyticalchemistry.eu/).

 

Tartu City Government acknowledged the organizers of Eurachem 2019!

On the 18th of February, the City Government of Tartu acknowledged the organizers of 14 international conferences that took place last year in Tartu, Estonia.

Mayor Urmas Klaas said that the high-level international conferences make Tartu visible in the field of conference tourism. In the future, the number of these well-organized conferences could be even higher, when Tartu becomes the European Capital of Culture in 2024 and additional flights from Tartu start to operate.

One of the acknowledged conferences was the Eurachem Workshop and General Assembly 2019, which was organized by the Estonian Center of Analytical Chemistry (ECAC)

Congratulations to the main organizer Riin and her team – Ivo, Anneli, Asko, Koit, Hanno, Jaanus, Pilleriin, Eliise and Siiri from our Analytical Chemistry Group for the well-deserved recognition! 

The secrets of two mummies have been unravelled

PLOS ONE has recently published a multidisciplinary paper on two Egyptian child mummies lead and participated by the members of our group. The team of 19 experts unravelled the secrets of two Graeco-Roman child mummies by applying most recent analytical techniques from archaeology, forensic sciences, analytical chemistry, medicine, entomology, and genetics. This is one of the most extensive multidisciplinary study of ancient mummies and the paper is free to download here.

Celebrating Christmas with our Analytical Chemistry family

Last week, the members of our Analytical Chemistry group celebrated Christmas together. 

After the traditional and tasty Christmas dinner, the not so traditional games took place. Everyone was dived into five teams. All of the teams had the same five tasks – they had to put their main senses to the test. But of course, the tasks required some additional knowledge of chemistry. 

The tasks were the following: identify common laboratory objects in a self-made and a not see-through “glove box” (touch); recognize the sounds of various laboratory machines, including the coffee maker (hearing); notice molecules and atoms in a drawing (sight); determine the concentrations of sugar solutions by tasting sugar solutions with known concentrations (taste); identify various alcohols and fragrant compounds by their aroma. The games of senses ended with a fun quiz.

                                   Touch

HearingSightTasteSmell

Wishing you happy holidays and a wonderful new year from our Analytical Chemistry group!

Jaanus Liigand was awarded the 1st prize in Estonian National Contest for University Students for his doctoral thesis

Jaanus Liigand was awarded the 1st prize in category of natural sciences and technology in the Estonian National Contest for University Students supported by Estonian Research Council for his doctoral thesis.

He defended his PhD thesis on “Standard substance-free quantification for LC/ESI/MS analysis based on the predicted ionization efficiencies”. During his PhD studies, Jaanus has worked hard on understanding the mechanism of electrospray ionization in LC/ESI/MS; primarily understanding how the structure of the compound and the eluent used in the analysis influence the ionization efficiency. Jaanus has verified, based on the largest set of ionization efficiencies measured so far (roughly 400 compounds), that the more hydrophobic compounds and more basic compounds tend to have a higher response in ESI positive mode. From the mobile phase point of view, both organic solvent contentpH of the buffer, and buffer composition, influence the ionization efficiency in ESI/MS. In general, higher organic solvent content and lower pH result in higher ionization efficiency and, therefore, a higher response in positive mode ESI/MS.

Dr. Piia Liigand and Dr. Jaanus Liigand

Also, he investigated how well are the ionization efficiency values measured on one instrument transferable to other instruments and found that with the aid of 5-6 common compounds the ionization efficiency values can be transferred from one instrument to another. Combining these promising results and machine learning approaches Jaanus has been able to develop a truly universal approach for applying ionization efficiency predictions for quantification in suspect and non-targeted LC/ESI/HRMS analysis.

He is continuing his research at University of Alberta in Canada in Prof. David Wishart research group to further improve mass spectrometric analysis with machine learning.

Congratulations to you, Jaanus, for the well-deserved acknowledgment!