The Workshop will take place in Tartu (Dorpat conference centre) on May 20th and 21st. The programme of the workshop, as well as registration and abstract submission are available at the event website: https://eurachem2019.akki.ut.ee/
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 workshop programme, because their validation involves specific issues (since analyte is not known it is not possible to make validation experiments with it) and 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.
Compact overview of the workshop can be found in the 2nd circular.
These events mark the 30th anniversary of Eurachem and are jointly organized by Eurachem and ECAC (University of Tartu, Tallinn University of Technology and the Estonian Environmental Research Centre).
The measured ionization efficiencies in different solvent systems. The colour of the box plot background shows the organic modifier (90%): Green – Methanol, blue – Acetonitrile, red – Acetone, orange – Isopropanol. The letter shows the water phase additive (10 mM): F – Formic acid, O – Oxalic acid, P – Propionic acid
Recently a study in Rapid Communications in Mass Spectrometry was published. In this study, we optimized the actual split ratio and make-up flow composition in LC/ESI/MS analysis to increase the signal in radio detector and enhance the sensitivity of electrospray ionization.
High methanol content increases electrospray ionization efficiency
We studied make-up flow composition with a set of 20 pharmaceuticals covering 21 different make-up flow compositions. We studied methanol, acetonitrile, isopropanol and acetone as organic modifiers. As we studied positive mode the acidic additives under investigation were formic acid, oxalic acid and propionic acid. DMSO and sulfolane as additives were studied as well. The Methanol/10 mM formic acid in water (90/10) proved to be the best make‐up flow composition in relation to the average sensitivity obtained. Stronger acidic conditions using oxalic acid or higher formic acid concentrations had a clear positive effect on the sensitivity of compounds with low ionization efficiency.
Split-ratios remain stable over main part of the gradient
The second part of this study was testing and monitoring different split ratios (1:10, 1:100 and 1:250) with different splitters (Alliance flow‐splitter kit and homemade T-piece splitter). To monitor the actual split ratio haloperidol solution was added with infusion pump post-column while a haloperidol-d4 solution was added as a make‐up flow by the ISM pump after the splitter. The tested split ratios were relatively stable over the main part of the gradient but showed some variation at very low and very high organic conditions. Differences were larger with methanol compared with acetonitrile containing solvent compositions and when applied without a column or with very long connecting tubing.
I thank Janssen Pharmaceutica and especially Dr Filip Cuyckens for the internship position for letting to gain experience in an industry setting and study these effects. Additionally, I thank Erasmus+ mobility and Smart specialization doctoral stipend for funding my stay.
13th biennial conference of Infrared & Raman User Group, shortly IRUG, was for the first time ever held in Sydney, Australia in a beautiful Art Gallery of New South Wales. IRUG conferences are gathering people using IR and Raman spectroscopy for the analysis of cultural heritage, architecture, and forensic materials. This year 101 people were attending, including Dr Signe Vahur and PhD student Pilleriin Peets from our group. Pilleriin was also introducing her results in analyzing textile fibres with IR spectroscopy in an oral presentation. Development of methods for the analysis of various textiles using ATR- and reflectance FT-IR spectroscopy turned out to be very relevant: throughout all three days, many people approached to discuss the topic, ask questions and advice or to make contacts for later cooperation. We were also very glad that conference participants were interested in our ATR-FT-IR spectral database of cultural heritage and conservation materials, available here.
Three days were filled with a wide range of interesting presentations from analysis of Aboriginal Australian pigments and identification of contents from the coffin of a 2500-year-old Egyptian mummy Mer-Neith-it-es to investigations of cultural heritage materials using neutron techniques. Besides the analysis of traditional pigments, organic pigments, especially synthetic organic pigments and their use in art were discussed (oral presentation by Dr Suzanne Lomax and Dr Steven Saverwyns). Another very interesting and thought-provoking presentation was done by Dr Gregory Smith from Indianapolis Museum of Art. He discussed the difficulties in getting accurate standard reference materials in the field of cultural heritage analysis. His results showing how many false materials can be found on the market (and not only vendors like Kremer Pigmente, but also providers like Sigma Aldrich) were very surprising.
All in all, IRUG 13 conference offered three full days of interesting presentations, a lot of knowledge and useful tips for further research and a pleasant atmosphere with excellent company.
Main concern while measuring ionization efficiency (IE) of derivatized compounds is that derivatized compounds are in complex mixtures. To overcome this problem, we developed a chromatographic method to separate these compounds and measure their ionization efficiencies.
If ionization efficiencies of derivatized compounds are measured without chromatographic separation in a complex mixture, which includes analytes, derivatization reagents and different by-products, then matrix effects could occur. This problem can be solved if we first separate these compounds from each other and then measure ionization efficiencies.
Chromatographic method
To separate different compounds, we used a simple chromatographic gradient elution method. One might think, that if compounds have different retention time, then they also elute at different organic phase percentages which obviously affects measured ionization efficiency values. The effect is not so significant, but we could manage to model it and take it into account to level all newly measured ionization efficiency values to a previously measured scale.
logIE measurements
We carried out ionization efficiency measurements with liquid chromatography electrospray ionization mass spectrometry (LC/ESI/MS) and constructed IE scales with a calibration curve for compounds with and without derivatization reagent diethyl ethoxymethylenemalonate (DEEMM). Additionally, we investigated eluent composition effects on ionization. Measured compounds were mainly amino acids but also included some biogenic amines.
Results
We saw, that
Derivatization increases IE for most of the compounds (by an average of 0.9 and up to 2 – 2.5 logIE units) and derivatized compounds have more similar logIE values than their underivatized variants.
Measurement of derivatized compounds is possible from the mixture when using chromatographic separation technique.
It was also noted, that using chromatographic separation instead of flow injection mode tends to slightly increase ionization efficiency.
We managed to link all our results with existing ionization efficiency scale and therefore widen the scale and get comparable logIE values for measured derivatized compounds.
The focus of the talk was sample preparation and how is it included in the EACH programme. A key feature of the presentation was a question to the participants as for what else could/should the EACH programme contain in terms of sample preparation, especially keeping in mind emerging techniques. Another one was a call to come to teach at EACH as visiting scholar. During the subsequent coffee breaks a number of people approached Ivo and interesting ideas were proposed as to what to include into the programme’s set of covered sample preparation approaches (dialysis, different microextraction techniques, sonication, etc). Several people also expressed interest to contribute to the programme as visiting scholars.
Call of applications to the EACH visiting scholar scheme is constantly open at the EACH Visiting scholars page and submitting of application is non-binding, so it is encouraged also if you are not yet sure whether you will come.
We are thankful to all participants for their feedback and ideas!
From 24th to 25th of November our group had a traditional biannual seminar in Pühajärve Spa hotel. The seminar is a nice opportunity to learn about what the group members are doing and which challenges they are tackling. The presentations covered a broad domain of analytical chemistry from fundamental acid-base studies to bioanalyses and analyses of cultural heritage.
Ambient ionization and fluoroalcohols to improve bioanalysis
The first session was focusing on the bioanalytics. Max, a PhD fellow doing an internship in London right now, presented the results of drug analyses from a music festival. Next to strongly varying drug dose, the problem is the strongly varying dissolution of corresponding dose. Next two presentations presented by Rūta, a PhD fellow, and Krit, her undergraduate student introduced fluoroalcohols as novel LC eluent additives and their effect on retention mechanism and electrospray sensitivity. It was really interesting how strongly and unexpectedly differently some fluoroalcohols may change the retention mechanism.
The reliability of fluorescence measurement
The second session focused on acid-base and coordination chemistry. Alo, a PhD fellow, presented his improvements and challenges in the synthesis of bambusuril derivatives. Elisabeth, a master student, introduced 19F NMR measurements of pKa of fluorinated compounds in acetonitrile. Sigrid, a PhD fellow, gave a lecture on how to measure correct fluorescence spectra accounting all effects that may affect the spectra. She showed the importance of concentration and the inner filter effects correction on fluorescence spectrum. Andre, a PhD fellow, wrapped up the seminar with the presentation of his results in gas phase acidity measurements.
Did I get real cashmere scarf from the market?
The third session was focusing on the analysis of cultural heritage. Eliise, a PhD fellow, presented the comparison of four most applied derivatization procedures for analysis of binders in GC. Pilleriin, a PhD fellow, presented her results of textile analyses and a model developed to classify unknown textiles using ATR-FT-IR spectroscopy. Markus, a master student, presented his work on coupling LC with nano-ESI FT-ICR-MS. Juhan, an undergraduate student, introduced his work on acid-base measurements of fluorophoric pH sensor molecules.
After inspiring presentation and fruitful discussions, we had a nice opportunity to relax in the spa and sauna. Additionally, group members discussed with Prof. Leito and Associate Prof. Herodes the SR-15 report from IPCC.
Is open science in terms of metadata really possible?
Next day was kicked off by Astrid, a PhD fellow, who compared the measurement of binding constants using isothermal calorimetry and NMR. Next, Piia, a PhD fellow, introduced her results on using the data from the literature to test, validate and improve the electrospray ionization efficiency prediction model. The take-home message from Piia’s presentation was the need for data integrity on results one is reporting and clear explanations on how one obtained these results. Additionally, a machine-readable format of the structure is a great help to simplify data mining from literature. Next, Jaanus, a PhD fellow introduced the results from a collaboration with a visiting PhD fellow Tingting Wang from DTU, Denmark. He showed the results of standard substance free quantification in the example of pesticides in food matrices. Ernesto, a PhD fellow, introduced his doctoral project on designing and describing the anionic derivatization reagents in LC/MS.
What’s causing this smell?
The second day was wrapped up by Associate Prof. Koit Herodes. He showed us a case study on the analysis of smell of ruined goods. Finally, he presented the current edition of validation software our group is developing to simplify and automate the validation in LC/MS analyses.
Thanks to all participants for interesting and inspiring presentation and for fruitful discussions.
Today, On Nov 16, 2018 the General Conference on Weights and Measures (CGPM) unanimously decided to fundamentally remake the SI system of measurement units. Perhaps the most important change is that the kilogram will not be defined via a physical artefact – the platinum-iridium cylinder – but in terms of the Planck constant. As a result, for the first time the entire SI system will be defined entirely on the basis of fundamental constants, which has been the aim for decades!
The change will become effective on the 2019 World metrology day – May 20, 2019.
The presentation started with explaining the need for the experimental realization and measurement capability of unified pH (pHabs). Thereafter the current state of art of measuring pHabs values was described and finally, some first exemplary results were highlighted.
The presentation created a lot of interest from the participants and roughly as many questions were asked as for the other four presentations of the same session put together!
As of now, it is not possible to compare pH values of solutions made in different solvents, as every solvent has its own pH scale. This situation is highly unfortunate, since it causes confusion and inaccuracies into many fields, extending far beyond the specific field of acid-base chemistry. Examples are industrial catalytic processes, food chemistry, liquid chromatography, etc.
The central aim of the UnipHied network is to establish at international level measurement capability of pHabs values that would be applicable also at routine laboratory level. The two key activities for achieving that are creating a reliable method for the experimental or computational evaluation of the liquid junction potential and between aqueous and non-aqueous solutions and developing a coherent and validated suite of calibration standards for standardizing routine measurement systems in terms of pHabs values for a variety of widespread systems (e.g., industrial mixtures, soils/waters, food products, biomaterials).
The partners of the UnipHied network are LNE (France, coordinator), BFKH (Hungary), CMI (Czech Republic), DFM (Denmark), IPQ (Portugal), PTB (Germany), SYKE (Finland), TÜBITAK-UME (Turkey), Freiburg University (Germany), ANBSensors (United Kingdom), FCiencias.ID (Portugal), UT (Estonia, initiator).
UnipHied 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.
The last part of the talk is devoted to the Eurachem 2018 General Assembly and Workshop that will take place in Tartu on May 20-21, 2018. The topic of the workshop is “Validation of targeted and non-targeted methods of analysis”.
Dr. Anneli Kruve defended her PhD thesis – “Matrix effects in liquid-chromatography electrospray mass-spectrometry” in University of Tartu in 2011 under the supervision of prof. Ivo Leito and dr. Koit Herodes. Right after she got her first personal funding and established the electrospray ionization efficiency studies group. In addition to understanding the ionization mechanism for small molecules in electrospray, she is interested in using charged nanodroplets generated by electrospray as an organic synthesis medium. In 2016 Dr. Anneli Kruve moved to Haifa, Israel to do her first post-doc at the Technion’s Schulich Faculty of Chemistry in Prof. Israel Schechter’s group. Right now, she is a Humboldt Fellow in the Institute of Chemistry and Biochemistry at Freie Universität Berlin in Germany in Prof. Christoph Schalley’s group.
In addition to excellent science, she is spreading the knowledge as she has designed and is actively lecturing different courses (instrumental analysis lab, statistics in analytical chemistry to name some) in analytical chemistry and statistics in analytical chemistry. She has also supervised several PhD and numerous MSc and BSc students.
Early inspiration
“I got started in organic synthesis but quickly joined a biomedical lab that needed students to operate a HPLC. From there, moving to LC/MS was a natural step. The ability to incorporate various skills from IT to synthesis with mass spectrometry-based research has kept me motivated to stay on this path.”
Research
“My field is structural and quantitative characterization of compounds with LC/ESI/IMS/MS. A key focus of mine is developing the possibility of giving a quantitative context to non-target LC/HRMS data without the need for standard substances.”
Greatest achievement
“I have already seen many students moving from our lab to the workforce and receiving positive feedback from their employers – that definitely makes a former supervisor happy!”
Prediction
“Mass spectrometry has already changed almost everything; its impact will increase further, as we make non-target screening more efficient with effective algorithms, and make it quantitative. I also have a dream technique: I sometimes wonder what the world would look like with MS-(gas phase)NMR . . .” (The Analytical Scientist)
We are very happy and proud that Dr. Anneli Kruve received this well-deservedly recognition of being nominated to the Top 40 Under 40 Power List by the Analytical Scientist!
Our group is proud to be the leading organiser of the 2019 Eurachem General Assembly and the accompanying scientific workshop “Validation of targeted and non-targeted methods of analysis”!
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.
