New Article Published: Analytical Chemistry

Think Negative: Finding the Best Electrospray Ionization/Mass Spectrometry Mode for Your Analyte

Previously our group has developed extensive ionization efficiency scales in ESI positive and negative mode. Thus far, the comparison between the two modes has only been qualitative. Due to use of different anchor compounds the scales were not quantitatively comparable. To solve this problem and to enable direct quantitative comparison of the two ESI modes we searched for an anchor compound ionizing to the similar extent in both modes. To find such a compound we combined mass spectrometry with laser induced fluorescence measurements (to find out the solvent composition and pH in the ESI droplets), NMR and UV-Vis (to characterize the potential anchoring compounds ionization degree in corresponding solvent). Trans-3(3-pyridyl)acrylic acid was found to be a suitable anchoring compound, if analysed in mobile phase with pH 4.00.

The link between two ESI modes ionization efficiency scales enables the user to choose the most optimal ESI mode for analysis for the analyte in question.

We also compared ionization efficiencies of 33 compounds ionizing in both modes and found that, contrary to general practice, negative mode allows higher ionization efficiencies for 46% of the compounds. For 18% positive mode ESI provides better ionization efficiencies and for 36% the results obtained in both modes are comparable. However, not all compounds can be ionized with ESI negative mode, and some unfortunately also not with ESI at all.

Published in: Piia Liigand; Karl Kaupmees; Kristjan Haav; Jaanus Liigand; Ivo Leito; Marion Girod; Rodolphe Antoine; Anneli Kruve; Anal. Chem. 
DOI: 10.1021/acs.analchem.7b00096

 

Measurement uncertainty online course (MOOC) 2017 edition successfully finished!

Measurement_Uncertainty_MOOC_Successfully_FinishedOn May 18, 2017 the MOOC Estimation of measurement uncertainty in chemical analysis offered by University of Tartu finished successfully.
Eventually altogether 363 people registered (270 in 2014, 489 in 2015, 757 in 2016) from 69 countries (a number of participants joined after the start of the course). The significantly lower number of participants is understandably due to the fact that this year for the first time the certificate on paper was not free of charge. 219 participants actually started the course (i.e. tried at least one graded test at least once) and out of them 148 successfully completed the course (141 in 2014, 169 in 2015, 308 in 2016). The overall completion rate was 41% (52% in 2014, 34% in 2015, 40% in 2016). The completion rate of participants who started the studies was 68% (67% in 2014, 60% in 2015, 67% in 2016). The completion rates of participants who actually started the course are nicely consistent over the 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. These 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 reached beyond 300 (!) (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 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 2018.

 

Textile analysis using ATR-FT-IR at Technart 2017

Pilleriin Peets presenting at Technart 2017
Pilleriin Peets presenting at Technart 2017

On May 02, 2017, the first day of the Technart 2017 conference (Bilbao, Spain) doctoral student Pilleriin Peets from UT Analytical Chemistry group made a presentation Identification and classification of textile fibres using ATR‐FT‐IR spectroscopy with chemometric methods (Photo on the left).

The presentation outlines the recent results by Pilleriin in creating the method for quick, easy and non-destructive classification and semi-quantitative analysis of textiles using ATR-FT-IR spectroscopy combined with chemometric data analysis methods.

She investigated altogether 89 individual textile materials – Wool, Silk, Cotton, Linen, Cellulose acetate, Lyocell/Tenzel, Viscose, Polyester fibre, Polyamide fibre, Polyacrylic fibre, Elastane and their different combinations – and created a discrimination/classification model using principal component analysis (Image on the right).

Classification of textiles by ATR-FT-IR and principal component analysis, PCA (single-fibre model)
Classification of textiles by ATR-FT-IR and principal component analysis, PCA (single-fibre model)

As a side-product of this work, a collection of ATR-FT-IR spectra of textile materials containing one or two different fibres was composed and is deposited in the Supplementary data of the paper that she recently published: P. Peets et al. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2017, 173, 175–181.

This collection of ATR-FT-IR spectra helps to identify a different kind of single- and two-component mixed textiles.

Technart conference series is a premier scientific forum dedicated to applying analytical techniques in the field of art and cultural heritage.

 

 

Rode Altarpiece Research and Conservation Project wins the EU Prize for Cultural Heritage / Europa Nostra Award 2017

Awards2017-Website&Facebook-share-1200x630On the 5th of April 2017 the European Commission and Europa Nostra announced the winners of the 2017 European Union Prize for Cultural Heritage / Europa Nostra Awards, Europe’s top honour in the heritage field.

Among the 29 laureates (from 18 countries) is also the Rode Altarpiece Research and Conservation Project (research category) of the high altar of St. Nicholas’ Church in Tallinn.

The project was coordinated by Dr. Hilkka Hiiop from the Art Museum of Estonia. This project also involves several scientists from the chair of analytical chemistry at the University of Tartu, among them Dr. Signe Vahur and her student Krete Saak, and Dr. Riin Rebane, who carried out a thorough material analysis.

The Award Ceremony will be held in Turku, Finland on the 15th of May 2017. During the ceremony, in addition to seven Grand Prix laureates also the Public Choice Award winner will be announced. Everyone has a chance to vote for 3 of their favourite projects, and thereby enter a draw to win a trip for two to Turku and take part in the European Heritage Awards Ceremony on 15th of May. The deadline for casting your votes is the 3rd of May, 2017.

Further information on the project can be found on the web page: Rode Altarpiece in Close-up.

Europa NostraLogoCreativeEuropeLogo

 

 

 

 

 

 

 

Measurement Uncertainty MOOC: 336 participants from 62 countries!

UT_Measurement_Uncertainty_MOOC_Participants_2017On Monday, March 27, 2017 the web course “Estimation of Measurement Uncertainty in Chemical Analysis” was launched the third time as a MOOC (Massive Online Open Course).

Currently 336 participants from 62 countries are registered. The somewhat decreased popularity of the course is most probably due to the fact that starting from this year certificate of completion on paper is not free of charge (digital certificate is still free). Given this change, we are actually surprised that we still have so many participants! Image on the left shows the countries where the participants come from. As in the previous years, the majority of participants are from analytical laboratories, once again demonstrating the continuing need for training in measurement uncertainty estimation in analytical chemistry.

The full course material is accessible from the web page https://sisu.ut.ee/measurement/uncertainty. Some developments and improvements have been made to the course material, in particular, better description of course organisatsion a self-test on sophisticated uncertainty estimation taking numerically into account the limited selectivity of the technique (potentiometry with ion-selective electrode). Some changes are still in the pipeline. 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. These tests are available to registered participants via the Moodle e-learning platform.

 

LC-MS Method Validation MOOC finished with 55% completion rate!

LCMS Method Validation online course offered by UTOn Feb 16, 2017 the MOOC LC-MS Method Validation finished successfully.
Altogether 303 people were registered from 61 countries. 224 participants actually started the course (i.e. tried at least one graded test at least once) and out of them 168 successfully completed the course. The overall completion rate was 55%. The completion rate of participants who started the studies was 75%. Both completion rates are all time highest that our group has seen in our MOOCs!

The questions from the participants were often very interesting, often addressed things that are really important to analysts in their everyday work and in several cases led to improvements in the course. 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 and some of them triggered making important modifications to the course materials.

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

We plan to repeat this course again in Autumn 2017.

 

EACH Winter School 2017 Ended

EACH_Winter_School_2017_Group_Photo_on_Lake_ErkenFriday 27.01.2017 was the last day of the EACH Winter School 2017. It appears to have been a memorable experience for all participants, especially those from southern countries. For example, quite some people had never walked on ice in their life, not to speak about jumping into water from sauna or under ice fishing! (See the previous post).

We were able to experience the best of Sweden – Swedish food, nature and hospitality, which was spiced up and complemented with exotic dishes and participants’ enthusiasm.

Sunset_on_Lake_Erken
The next Winter School will take place in January 2018 in Lyon.

Photos by Jayaruwan and Jonas: group photo and beautiful sunset on Lake Erken.

 

EACH Winter School: Fishing on Lake Erken!

Wednesday Jan 25, 2017: a major entertainment on that day of the Winter School was a short fishing trip to the nearby lake
Erken.

Photos by Santosh, Sadakat and Jayaruwan:  🙂

New logo of EACH

The lake is covered with ice and the participants had to use an ice drill for making the holes for fishing. It was a lot of fun and an exotic entertainment for those from southern countries!

EACH Winter School 2017 Started!

EACH_Winter_School_2017_Group_Photo
On Jan 23, 2017, the second Winter School of the EACH programme started in Erken Laboratory (Erken, Sweden). Altogether 34 students from more than 20 countries participate.
The Winter School offers a diverse set of activities to the participants. There are lectures on advanced analytical chemistry topics by top experts, group works and entertainment. Several sessions are presented by industry practitioners. The intense working is counterbalanced by social activities.

Uppsala_Students_Presenting_their_Master_Thesis_TopicsProf_Jonas_Bergquist_enjoying_Presentations

 

Traditionally an important activity in the Winter school is selecting first year students to study tracks. In order to give one more piece of information what the study tracks are about, there was a session of presentations on the first day by second year students on their master thesis topics.

Students_Watching_Presentation
Full information about the Winter School activities is available at the EACH Winter School web page.

Group Photo (Jayaruwan Gunathilake): in front of the main building of the Erken Laboratory; Photos in the middle (Ivo Leito): Uppsala students presenting their master theses and prof. Jonas Bergquist enjoying their presentation; Photo on bottom left (Ivo Leito): Vietnamese students following the presentation.