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

 

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

 

 

 

 

 

 

 

UT analytical chemistry education activities at CroLab “Laboratory Competence 2016″ Conference

Leito_CroLab_2016On Oct 20, 2016 Ivo Leito gave presentation titled Education Activities in Metrology in Chemistry in Vinkovci (Croatia) at the conference Laboratory Competence 2016 organized by CroLab – the Croatian Association of Laboratories.

The presentation contains information about the Applied Measurement Science and Excellence in Analytical Chemistry master’s programmes et University of Tartu, about the international consortium Measurement Science in Chemistry, about the on-line course Estimation of Measurement Uncertainty in Chemical Analysis and the new on-line course LC/MS Method Validation. Also the recently published tutorial reviews were touched upon.

The presentation led to a number of new contacts and invitation to next events. Participants were impressed by the breadth of activities as well as by the very strong team working on these things at UT. In addition, Ivo Leito was interviewed by the Croatian national television.

 

EcoBalt 2016 Successfully finished!

EcoBalt_2016_Group_PhotoOn Wednesday 12.10.16 the EcoBalt 2016 conference – first time organized in Tartu, Estonia – finished successfully! 42 oral talks and 43 posters were offered to the more than 150 participants from more than 25 countries. The conference featured two tutorial sessions – on measurement uncertainty and on validation of LC/MS analytical methods. The mesmerizing introductory multimedia presentation by Sven Zacek about Estonian nature and the stunning closure talk about “impossible things” by Meelika Hirmo from Let’s Do It! World were certainly among the highlights of the conference.

A number of AMS and EACH students participated in the conference.

We thank all the participants for making EcoBalt 2016 a success!

Full information about the conference, including the conference programme and EcoBalt 2016 Book of Abstracts can be found at the EcoBalt 2016 website.

EcoBalt 2016 was organized by the University of Tartu with Tallinn University of Technology and Estonian Environmental Research Centre.

EcoBalt2016 received financial support from a number of sources. We thank all supporters! Without their help the conference would not have been possible.

  • For organisation of international events and conferences from Estonian Ministry of Economic Affairs and Infrastructure in cooperation with the Enterprise Estonia tourism development centre from funding provided by the European Union Regional Development Fund.
  • Second day of the conference was fully supported by Environmental Investment Centre.
  • The following companies supported the conference: LaboChema, Ramboll, Ordior, Quantum, SyntPot, HNK, Waters, Armgate and LanLab.

EcoBalt 2016 starts today!

eesti-keskkonnauuringute-keskus_riidekoti_kujundusIn few hours the EcoBalt 2016 conference will start, for the first time in Tartu!

The EcoBalt conference series has traditions dating back to 1993 and has been envisaged from the beginning as a Baltic event. Nevertheless, this is the first time that it takes place in Estonia (previously only in Latvia and Lithuania).

We are very glad to welcome more than 160 registered participants from more than 25 countries, making it a truly international conference! The nearby countries are represented as well as e.g. Philippines, Mexico, India, China, Nepal, Sri Lanka, … A number of EACH students also participate in EcoBalt 2016!

The EcoBalt 2016 programme is very diverse: topics ranging from ultramodern environmental analytical techniques to environmental management and from nanoparticles in environment to global climate change.

EcoBalt 2016 is organised jointly by UT in collaboration with TTU and Estonian Environmental Research Centre in the framework of the ECAC consortium.

 

EuCheMS 2016: MOOCs in teaching analytical chemistry at University of Tartu

mooc_vs_traditional_courses_in_chemistryOn Sept 13, 2016 Ivo Leito gave a presentation Using MOOCs for teaching analytical chemistry: experience at University of Tartu at the EuCheMS 2016 Congress (Seville, Spain).

The presentation outlined the contents and organisation of the material in the on-line course Estimation of measurement uncertainty in chemical analysis, the different ways of using the on-line material (for independent learning, for self-testing, as an information source and as a basis for running as a MOOC) and the experience of running it as a MOOC (Massive Open Online Course) at University of Tartu during the three MOOC editions in 2014 to 2016. An important part of the presentation was devoted to analyzing the pros and cons of MOOCs as a way of teaching and in particular as a way of teaching analytical chemistry (or its subdisciplines). It was concluded that MOOCs do have advantages, especially if compared to short training courses for practitioners. The talk created quite some interest and discussions after the session.

Detailed discussion of this topic has been published: I. Leito, I. Helm, L. Jalukse. Anal Bioanal Chem 2015, 407, 1277–1281.
The course material is available for all interested people from https://sisu.ut.ee/measurement/

Preparation of a new MOOC course Validation of LC-MS analysis methods is currently underway by the group of analytical chemistry. The materials of the LC-MS validation course are nearing completion and are already available online.

New EACH and AMS students started their studies!

EACH_and_AMS_Students_UT_2016This week was the first study week for the new Applied Measurement Science students and EACH Erasmus Mundus. Altogether 19 students started their studies. The countries of origin of the students are Vietnam, Philippines, Russia, Serbia, Kazakhstan, China, Sri Lanka, Nepal, Nigeria, Mexico, Lithuania, Tunisia, Pakistan and Greece. During the introductory meeting an overview of the programme was given (see the slides) and a large number of questions were asked and answered, accompanied by tea/coffee and cake.

We wish successful studies to all new students!

 

What is the best LC-MS ion source? How to determine Limit of detection of a method?

Asko_Laaniste_Hanno_EvardThese very important (and up to now not completely solved) questions got a lot clearer on Aug 31, 2016 as PhD dissertations addressing these topics were defended at UT Institute of Chemistry.

Asko Laaniste (left on the photo) in his thesis titled “Comparison and optimisation of novel mass spectrometry ionisation sources” and in the recent paper ESI outcompetes other ion sources in LC-MS trace analysis Anal. Bioanal. Chem. 2019 has carried out an extensive experimental comparison of 4 different LC-MS ion sources operated altogether in 7 different modes in the analysis of 41 different pesticides. The obtained large pool of data was used for comparing the sources in terms of matrix effects, limit of detection (LoD), repeatability, linearity, signal to noise ratio (S/N) and sensitivity.

Asko demonstrated that for low levels of analytes in most cases the conventional ESI is the ion source of choice (provided the analytes are ionizable with ESI), while dopant-assisted APPI is a good alternative if low detection limits are not required and if compounds not ionizable with ESI are determined.

This is currently the most comprehensive comparison of this type available and Asko’s thesis (and the forthcoming publication) could serve as a “desk manual“ for LC-MS practitioners on choosing ion source for LC-MS analysis.

The central question of Hanno Evard’s thesis “Estimating limit of detection for mass spectrometric analysis methods” and in the corresponding two-part tutorial review Tutorial on estimating the limit of detection using LC-MS analysis (Anal. Chim. Acta 2016, 942, 23-39, Anal. Chim. Acta 2016, 942, 40-49) was: what is the best way of evaluating detection limit (LoD) of an analytical method? There are around ten widespread approaches for LoD in the literature (plus less well known ones) and the LoD values obtained using different approaches can differ by up to 10 times.

Hanno (right on the photo) carried out comprehensive analysis of the literature approaches and combined that with extensive experiments. As a result he was able to propose and convincingly justify one approach, which has merits over others and should be used for evaluation of LoD.

Hanno Evard is an alumnus of the Applied Measurement Science programme – the predecessor programme of EACH.

Our warmest congratulations to Asko and Hanno!

EcoBalt 2016: the programme is converging nicely!

We are glad to announce that the EcoBalt 2016 programme has been converging nicely – we have now a lot of interesting presenters! At the same time there are still free slots so that we continue to accept abstracts both for oral and poster presentations. The conference takes place in Tartu (Estonia) during 9.-12. October 2016.

In addition to the scientific content the EcoBalt 2016 conference will be hosting two tutorial classes with the following topics:

— Tutorial on measurement uncertainty (Oct 09, 2016)
— Tutorial on LC/MS method validation (Oct 12, 2016)

Both of these will be interactive sessions oriented towards solving practical questions, making decisions in measurement uncertainty and validation, performing calculations, etc. The tutorials assume basic knowledge of the topics – measurement uncertainty and validation, respectively. There is no extra fee for the tutorial classes – the conference fee covers also the tutorials. If you are interested in participation in one or both tutorial classes, please register to the EcoBalt 2016 conference.

The registration is still open at the EcoBalt 2016 website.

The most current information is in the EcoBalt 2016 4th circular.

We also have created the EcoBalt 2016 Facebook page where all the latest news are presented.

If any questions, do not hesitate to contact the local organizers, Dr Riin Rebane (riin.rebane@ut.ee) or Prof Ivo Leito (ivo.leito@ut.ee).

EcoBalt 2016 is an environmental science conference, with a strong focus on environmental analytical chemistry and metrology/quality aspects of analytical measurements and there will be a special session there dedicated to these topics.