During May 20-21, 2019 the Eurachem 2019 Scientific workshop Validation of targeted and non-targeted methods of analysis took place in Dorpat Conference Centre in Tartu. This workshop also marks the 30th anniversary of Eurachem.

Approximately 160 people attended the workshop, which is the largest number of participants in the history of Eurachem workshops! The participants were from 42 countries of the member countries in Eurachem as well as Asia, North America, South America and Middle East. The farthest participants were from Fiji, the Philippines, Uruguay and Brazil.

The workshop was held with 13 oral presentations from established researchers, young scientists as well as industries. Together with 22 posters all presentations reflected the current and potential future developments related to methods validation. The workshop addressed the current status of analytical method validation in general and specifically validation of the non-targeted methods (i.e. ones where the analyte is not defined beforehand). With the speaker permissions, all presentations will shortly be available at the Eurachem website. In addition to presentations, each day a Working Group session was organised with 3 topics in parallel (Image on the left: Welcome by Dr Marina Patriarca, the Eurachem chair).

Non-targeted methods are an especially noteworthy part of the programme, because their validation involves specific issues and their validation is significantly less developed than validation of targeted methods (i.e. the “normal” analytical methods, where the analyte is known beforehand). At the same time non-targeted methods are becoming increasingly important in environmental protection, food safety, different omics areas, etc. (Image on the right: Prof. Jon Benskin from Stockholm University presenting an introduction to non-targeted analysis)

All sessions raised new issues and challenges, especially related to non-target method validation. The workshop clearly was also very inspirational for Eurachem from the point of view of preparing new guideline materials – especially the topics related to non-targeted analysis are still essentially not covered by official guidance documents.

Some example topics of the workshop: Validation of targeted methods: where are we? Validation of non-targeted methods – differences from targeted methods. Detection of a multitude of (unknown) components in complex samples: criteria for identification. Managing the huge amounts of complex data from non-targeted methods. Recent instrumental developments. Software tools for validation. (Image on the left: Dr. Koit Herodes presenting the ValChrom validation software)

The workshop certaily had a significant educational value and we are pleased by the large number of student participants: altogether close to 50! The international master’s programmes Excellence in Analytical Chemistry and Applied Measurement Science were both heavily represented: the majority of students of those programmes participated in the workshop (Image on the left: EACH and AMS students at the workshop).

The workshop was jointly organized by Eurachem and ECAC (University of Tartu, Tallinn University of Technology and the Estonian Environmental Research Centre).

 

Measurement_Uncertainty_MOOC_Successfully_FinishedOn May 14, 2019 the on-line course (MOOC) Estimation of measurement uncertainty in chemical analysis offered by University of Tartu finished successfully.
Eventually altogether 590 people registered (270 in 2014, 489 in 2015, 757 in 2016, 363 in 2017, 521 in 2018) from 86 countries (a number of participants joined after the start of the course). 381 participants actually started the course (i.e. tried at least one graded test at least once) and out of them 238 successfully completed the course (141 in 2014, 169 in 2015, 308 in 2016, 148 in 2017, 358 in 2018). The overall completion rate was 40% (52% in 2014, 34% in 2015, 40% in 2016, 41% in 2017, 42% in 2018). The completion rate of participants who started the studies was 62% (67% in 2014, 60% in 2015, 67% in 2016, 68% in 2017, 61% in 2018). The completion rates are consistent over the last years and can be considered very good for a MOOC, especially one that has quite difficult calculation exercises, which need to be done correctly for completing the course.

The participants 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) and the overall number of posts to them during the course period exceeded 400 (!) (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 of this MOOC a great experience also for us, the teachers. The discussion threads gave a lot of added value to the course and some of them triggered making important modifications to the course materials, even during the course.

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

We plan to repeat this course again in Spring 2020.

 

Choosing the best possible ion source is a very important step in liquid chromatography mass spectrometry (LC/MS) method development. In a recent paper ESI outcompetes other ion sources in LC-MS trace analysis Anal. Bioanal. Chem. 2019 Asko Laaniste from the UT Analytical chemistry group carried out a large scale survey of differen LCMS ion sources (and their different working modes) as applied to pesticide analysis. He compared electrospray ionisation (ESI) source, thermally focused/heated electrospray (HESI), atmospheric pressure photoionisation (APPI) source with and without dopant, and multimode source in ESI mode, atmospheric pressure chemical ionisation (APCI) mode, and combined mode using both ESI and APCI, i.e. altogether seven different ionisation modes for the analysis of 40 pesticides (see list below).

The lowest limits of detection (LoDs) were obtained by ESI and HESI. The widest linear ranges were observed with the conventional ESI source without heated nebulizer gas. ESI source was significantly less affected by matrix effect than the HESI source. APPI ranked second (after ESI) by not being influenced by matrix effect; therefore, it would be a good alternative to ESI if low LoDs are not required.

It was somewhat unexpected that ESI outperformed HESI. This may be caused by the instability of the additional heated gas (sheath gas) in HESI that is used in addition to the nebulising gas.

In conclusion, as a broad generalisation, Asko’s results show that although several new ion sources have been introduced during the last decade, the conventional ESI performs at least equally to these new ion sources in the case of polar to medium polarity pesticides. ESI with thermal focusing (HESI) performed more or less equally with ESI in terms of LoD. At the same time, HESI had significantly poorer intermediate precision of matrix effect values for most compounds. Thus, for trace analysis, ESI is still the ion source of choice.

(Full list of pesticides: pymetrozine, thiamethoxam, methiocarb-sulfoxide, chloridazon, imidacloprid, acetamiprid, methiocarb-sulfone, thiacloprid, imazalil, thiophanate-methyl, metribuzin, pyrimethanil, fenpropimorph, spiroxamine, propoxur, triasulfuron, bupirimate, paclobutrazol, methiocarb, azoxystrobin, epoxiconazole, myclobutanil, fenhexamid, fluquinconazole, flusilazole, mepanipyrim, bitertanol, propiconazole, triazophos, methoxychlor, ditalimfos, tebufenozide, benalaxyl, pyrazophos, buprofezin, indoxocarb, trifloxustrobin, quinoxyfen, pirimiphos-ethyl, hexythiazox)

 

(Image top left: Asko Laaniste preparing solutions; Image right: Comparison of accuracy of LC-MS analysis using different ion sources)

 

On Tuesday, March 26, 2019 the web course Estimation of Measurement Uncertainty in Chemical Analysis was launched the sixth time as a MOOC (Massive Online Open Course)!

Currently 530 participants from more than 80 countries are registered! 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 also forms a part of the measurements and chemical analysis related master programmes at UT: Applied Measurement Science and Excellence in Analytical Chemistry.

 

Starting from last week the Analytical chemistry group of University of Tartu has the pleasure to host Dr Monika Lindner and Hendrik van Thienen from the group of professor Benjamin List – a worldwide known guru in the field of strongly acidic catalysts working at the Max-Planck-Institut für Kohlenforschung (Mülheim, Germany).

The purpose of their stay is to learn our pKa measurement method and set it up in Mülheim. This is the logical continuation of our group’s collaboration with the List group – the pKa values of a number of their catalysts have been measured here at Tartu (see Nature Chemistry 2018, 10, 888-894 and Angew. Chem. Int. Ed. 2017, 56, 1411-1415) – and we are glad that our pKa measurement method thereby gains even wider acceptance than it has now. We wish Monika and Hendrik all the success in learning the measurements!

(On photo, from left: Märt Lõkov, Monika Lindner and Hendrik van Thienen)

 

During 24-26.02.2019 the Suprachem 2019 conference took place at University of Würzburg (Germany). The UT Analytical chemistry chair was represented by two posters: Optimization of the reaction pathway for the synthesis of substituted 1,3-bis(carbazolyl)urea anion receptors by Alo Rüütel and Mihkel Ilisson and From receptor-anion binding ladder to ion-selective electrode by Kerli Martin, Sandip A. Kadam, Ulriika Mattinen, Johan Bobacka and Ivo Leito.

The presentation from Alo and Mihkel focused on optimization of the synthesis route of anion receptors (ionophores) based on the 1,3-bis(carbazolyl)urea building block, augmented with additional amide functionalities (see the poster). The developed synthesis route is very valuable for the synthesis of a wide variety of analogous receptors (ionophores) that have previously been demonstrated to bind carboxylates with high affinity (see K. Martin et al, Eur. J. Org. chem. 2017, 5231-5237).

Kerli Martin et al present the first practical application of such receptors: a solid-contact acetate-selective electrodes. For acetate anion the electrodes show linearity over the activity range of 10-4.50 – 10-1.10 with a sub-Nernstian slope of -51.3 mV per decade and a detection limit of 10-5.00. The anion-selectivity pattern of these electrodes deviates markedly from the pattern found in DMSO solution and from the Hofmeister pattern. The selectivity coefficients of SCN, I, NO3 and Br decrease by 3-5 orders of magnitude when adding the studied ionophore to the membrane. The selectivity coefficients of hydrophilic anions such as Cl, F, HPO42–, and SO42– are significantly lower than in case of the ionophore-free control membrane. All in all, it is clear that a lot of work is still needed for improving the selectivity of the electrode.
This work has been accepted for publication: K. Martin et al Electroanalysis 2019 (the link will work soon).

The combined contributions from our group stood out from the majority (the conference altogether had 27 oral and 111 poster presentations) by a clear line of development from fundamental research (receptor design) to highly practical application (ion-selective electrode).

(Photos: above left: Mihkel Ilisson explaining his work to Dr Diane Smith from Wiley; right: Poster by Kerli Martin et al)

 

LCMS Method Validation online course offered by UTOn Feb 15, 2019 the on-line course (MOOC) LC-MS Method Validation finished successfully!
Altogether 426 (424 in 2018, 303 in 2017) people were registered from 70 countries (71 in 2018, 61 in 2017) countries. 227 (236 in 2018, 224 in 2017) participants actually started the course (i.e. tried at least one graded test at least once) and out of them 125 (159 in 2018, 168 in 2017) successfully completed the course. The overall completion rate was 29% (37% in 2018, 55% in 2017). The completion rate of participants who actually started the studies was 55% (67% in 2018, 75% in 2017). As can be seen, almost all these statistics have been getting worse year after year. We are working n analysing the situation. On the positive side it can be said that the completion rates more than 0% of those who started can be considered very good by any measure. Thus we probably can be reasonably happy with the completion rate that we have this time.

As has been the usual case with our online courses, the questions from the participants were often very interesting, often addressed things that are really important to analysts in their everyday work. Such discussions made teaching this course a great experience also for us, the teachers!

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

We plan to repeat this course again in Autumn 2019.

 

 

The 2019 edition of the web course (MOOC) Estimation of Measurement Uncertainty in Chemical Analysis will be running during Mar 26 – May 7, 2019. Registration is open!

The full course material (as well as the registration link) 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 take six graded tests and get higher than 50% score in every graded test. These tests are available to registered participants via the Moodle e-learning platform. Participants who successfully pass the course will get a certificate from University of Tartu. A digital certificate of completion is free of charge. A certificate of completion on paper can be requested for a fee of 60 euros.

You are welcome to distribute this message to potentially interested people!

We are pleased to announce that the 2019 Eurachem general Assembly and the scientific workshop Validation of targeted and non-targeted methods of analysis will take place in Tartu!

The Workshop will take place on May 20th and 21st; the General Assembly will take place on May 23rd to 24th. The preliminary programme of the workshop, as well as registration and abstract submission are available at the event website:
https://eurachem2019.akki.ut.ee/

Compact overview of the workshop can be obtained from the First Circular.

The workshop addresses the current status of analytical method validation in general and specifically validation of the non-targeted methods (i.e. ones where the analyte is not defined beforehand). Non-targeted methods are an especially noteworthy part of the programme, because their validation involves specific issues (since analyte is not known it is not possible to make validation experiments with it) and their validation is significantly less developed than validation of targeted methods (i.e. the “normal” analytical methods, where the analyte is known beforehand). At the same time non-targeted methods are becoming increasingly important in environmental protection, food safety, different omics areas, etc.
Some example topics of the workshop are: Validation of targeted methods: where are we? Validation of non-targeted methods – differences from targeted methods. Detection of a multitude of (unknown) components in complex samples: criteria for identification. Managing the huge amounts of complex data from non-targeted methods. Software solutions for validation.

These events also mark the 30th anniversary of Eurachem.

These events are jointly organized by Eurachem and ECAC (University of Tartu, Tallinn University of Technology and the Estonian Environmental Research Centre).

 

Recently the Analytical chemistry group of University of Tartu participated in a cutting-edge research endeavor: characterizing the acidity of some extremely efficient strongly acidic organocatalysts. In the case of the Mukaiyama aldol reaction the best of them (1) worked at low ppm to sub-ppm level, (2) gave excellent yields and (3) high enantiomeric selectivity as well as (4) turnover numbers (TON numbers) of hundreds of thousands (Nature Chemistry 2018, 10, 888-894).

The extent to which these four features occurred together in the same catalyst was so remarkable that the results were published in one of the most prestigious journals in chemical sciences: Nature Chemistry.

The extremely demanding acidity measurements were performed by Dr Karl Kaupmees using the unique non-aqueous acid-base chemistry facility that the group is running. The whole research project was led by the group of professor Benjamin List – a worldwide known guru in the field of strongly acidic catalysts working at the Max-Planck-Institut für Kohlenforschung.
These results are expected to open new avenues in development of powerful new organocatalysts.

(Photo by Andres Tennus: Karl doing acidity measurements in a glovebox under anhydrous conditions)