Recognition of Piia and Jaanus on scientific works competition

This week two of my students have been recognized by different organizations for their outstanding scientific work. Jaanus Liigand received first prize in the field of natural science for his Masters thesis “Electrospray ionisation efficiency scales: mobile phase effects and transferability” on a scientific works competition by Estonian Research Council. Also our (the theses were supervised by me and Karl Kaupmees) student Piia Liigand (Burk) was nominated and awarded by Estonian Academy of Science for her work “Expanding the electrospray ionization efficiency scale in positive and negative mode ESI”.

By now all three parts of Jaanus’ thesis have been submitted for publication. The last part on pH effect was submitted only on Tuesday. Piia has also by now submitted a paper on her first task about multiply charged compounds’ ionization efficiency.

Both of the students are continuing their work as PhD students in our lab. We hope to see a lot of good science also during next four years!

Environmental conference in Tartu

In a bit less than a year an international conference EcoBalt will be held in Tartu.  The conference will last for 4 days 9.-12.October 2016. This is the first time EcoBalt will be held in Estonia, though it has taken place in Baltics for more than 15 years now. The conference is organized by University of Tartu. The conference focuses on environmental problems as well as technological developments for environmental analyses.

A real bonus for young scientist is the special session dedicated to young researchers in the environmental field. Of course oral presentations (in parallel sessions!) and poster sessions will be part of this conference. Also a very attractive social program in planned. The abstract submission will be opened from December.

Hope to see a lot of you there!

Check out more information: http://akki.ut.ee/ecobalt-2016-2/?lang=en

Plastics and food

Yesterday for the first time I saw a catalogue of a famous company producing and selling cooking accessories. And I soon become puzzled. A lot of people fancy these products lately, however everything they produce is made out of plastic.

My family and some of my closest friends are well aware that I have never been a huge fan of plastic packed things. I try not to take a plastic bag in shops if possible. In the beginning my mom even tended to be a bit annoyed by this habit of mine. It seems to me so unsustainable to produce large sets of consumables inside packages that are only seldom reused and produce almost nondegrading waste.

Another question of course is the safety of the plastic packages to people. Though there are plastics with numbers 2 (HDPE), 4 (LDPE) and 5 (PP) that have been considered safe, it is well known that even for these plastics the research has not fully proven their safety. This discussion reminded me of a high-school student’s research on a similar topic.  

Last year in Institute of Chemistry Kerttu Taltsi carried out her student scientific work under supervision of Tõiv Haljasorg. Her topic was leaching of phthalates from plastics with FT-ICR-MS. One of the most considerable finding of this work for our everyday life is that even from plastic no. 5 a detectable amount of plastificators leached into water during 30 days (at 60 °C). She discovered leaching of 3 different phthalates and one previously unidentified plasticizer. The leaching experiment was carried out with pure water. These conditions are not directly comparable to our everyday usage of plastic storing boxes. Usually we do not store one food so long in one box. However often we store food which has low pH and/or warm it up in the micro inside the same plastic box. More information about this research is available from Tõiv Haljasorg.

It seems that more research is needed in the field of safety of plastics though their unsustainability can hardly be argued. 

Sporty chemists

Most certainly the event of the week has been the Tartu city marathon and more precisely the competition between labs held during this marathon. Our students organized a competition “which lab has the highest participation rate on the city marathon”.

The “event” for our institute actually started even a lot earlier as several people not running on everyday bases started practicing together after the work-school days.

As the race was held on 3 distances 42, 21 and 10 km there was something for everyone. Altogether 57 people from Chemistry Institute took part in this event. Including professors, scientists, and students.

It was quite nice to have that many friends on the track and by the track! Though I had not planned to make another half marathon this year the lab competition brought me to the track and it certainly was a good choice. The weather was awesome and running together with friends was a lot better than I had expected. I was even able to improve my personal best. 

Analytical chemistry group on the Tartu city marathon.

No sample pretreatment?

Do you want to screen the pesticides presence on your orange? Or do you want to determine if person has used illegal drugs? Or maybe you want to determine the contamination level of trees in the park across the street?

How many sample preparation methods do you need for this? The answer is simple. Just one.

You need a PSI/MS. This means a mass-spectrometer (MS) with a paper spray ionization (PSI) source.

Paper spray was invented approximately 5 years ago in Prof. G.R. Cooks lab. This is a technique that allows to analyse samples that have been collected on a paper with MS.

A PSI/MS setup. Author Hanno Evard.

You can analyse dried blood spots and determine metabolites indicating some disease or determine doping chemicals. Just from this one small blood spot. The beauty of the method is that you really do not need to do anything more than place the blood spot bunched out from the collection paper to the cartridge (placed in front of the MS entrance and to which the ionization voltage is applied to) and add solvent. Both sample preparation and ionization occurs then on the paper and in the spray. Sample preparation can be modified by choosing different paper type (chromatographic papers, eg containing silica or C18 modified silica).

I our lab we have mostly used PSI for pesticide determination. The easies application is for pesticides that are located on the peel of the fruit (the ones that are applied after harvesting). For example thiabendazole and imazalile on oranges, lemons, grapefruits etc. You just need to wipe the peel of the fruit with a paper wetted with solvent and put this paper into PSI/MS. It is a bit trickier for compounds that have been applied during cultivation. For these compounds a slice (or a mush) onto the paper and then apply the solvent.

You can find more about our work on paperspray here.

Are all ESI/MS instruments the same?

The second paper on my students Jaanus Liigand master’s thesis was published recently. During his master’s he effectively showed that ionization tendencies of analytes in ESI source are independent of the source design and mass analyser of the 

Altogether 15 compounds with varying properties were measured on 5 instruments (here and in Lyon) and two solvent systems. The statistical treatment (t-test and correlation analyses) results showed that there is no reason to expect large variations between analyte responses between instruments.

Importance of this work? (1) Relating ESI/MS responses with analyte properties is possible (we do not have to take into account source or instrument parameters). (2) Ionization efficiencys already available in the literature are universal and can be used by groups having different instrumentation. 

So to return to the original question, of course different instruments have different sensitivity and many of them may work under very different conditions (voltages, gas flow rates and temperatures) but the large picture for ESI/MS ionization stays the same.

Future perspective? Of course different solvent systems have different effect on ionization efficiencies (protonation, adduct formation, etc) and unfortunately scientist can still only generally predict and explain these effects.

Link to the paper

Applying for Marie Curie fellowship: my proposal submitted

Yesterday I submitted my proposal for becoming a Marie Sklodowska-Curie fellow. So if everything goes as hoped I will be collaborating with Prof. Christoph Schalley group in Free University of Berlin from the next schoolyear. My project there will be about supramolecular chemistry, more precisely on rotaxanes and molecular machines based on rotaxanes. It will introduce me a whole new world of opportunities that exist in supramolecular chemistry. I am really excited about this stay, though it is not certain jet.

I would like to comment on some things that I have learned about myself and about applying during this process. First of all, few years ago I was sure I never want to go to post-doc. There were several reasons. I had my aims that could at that moment of time be fulfilled here in University of Tartu. This has changed, I feel the need to learn some new tricks to reach higher, to be more effective and to widen my collaboration circle. Secondly I have always been very keen on my family. My stay in Helsinki during my doctorate thought me that far away from home (alone) can be somewhat depressing. Though I have grown and also Tauri is now able to come with me to Berlin, so this hard part can be handled. I am really grateful that Tauri is willing to take this effort for my dreams and take a break in his career.

Actually the fact that this proposal is now submitted sounded unrealistic to me in April. Everyone who had either applied for MSC or had heard anything about it told that it is very-very-very (I should probably but an exponent here) hard. And to be honest the form itself also felt quite complicated in the first place. But as the discussion with Prof. Schalley went further a plan that I felt comfortable with was put together and then it wasn’t that complicated to put it down on paper. I am also very thankful to everyone who helped me during this period – starting from discussions on the topic down to taking up some of my duties so that I would have a bit more time to focus on the proposal. Thank you all very much!

What I would like to say to everyone who will be applying to MSC or something similar, even though it seems hard in some point, writing the proposal can really help you. During this period I have written to numerous people I did not even know about before, aiming to gain some information (mostly about how things will be organized in FU when I start my fellowship). And though it seemed a bit weird to me in the first place that I am asking people about things that are not even certain jet, I started feeling must more confident about the success of my stay. Due to these interactions, I hope, I have a more realistic picture what happens when I arrive in Berlin. Which on the other hand has made me feel that it is a right thing to do and I really want to do it.

Another important thing is the influence I have already had. During writing this project I have to admit I read more papers then probably during the whole year before. Which, in the beginning seemed like an ocean, but though I still probably haven’t read a fraction of papers related to my topic in Berlin I have already found a lot of interesting stuff that also is related to my tasks (scientific and partially also teaching) today. And these came up from the papers I would have never been searching from.

I will keep my fingers crossed until the time results of this proposal will become available (Feb 2016). 

A new competence centre in Southern Estonia

Last week I had a change to visit a brand new Polli laboratory of the Estonian University of Life Sciences together with our student Elmo. The Polli lab is located in Southern-Estonia near Karksi-Nuia and surrounded by breathtaking landscape with hills and lakes. The Polli laboratory is unique in Estonia as it combines equipment suitable for small scale industrial testing as well as high competence analytical laboratory.

The analytical laboratory is equipped, in addition to other high-tech instruments (including LC/MS etc), with a SFC/MS (super critical fluid chromatography – mass spectrometry) instrument which can be online coupled with SFE (super critical fluid extraction) instrument. The aim of this high-tech lab is to support the development of functional foods produced in Estonia but also to provide research on the functional components of natural products.

The industrial part contains several extraction instrumentation – microwave extraction, supercritical fluid extraction, pressurised liquid extraction - as well as different mixers, lyophilizators, sieves, etc. The extraction equipment is specially chosen so that it would allow production of extracts of functional components for small batches of foodstuff. Also Polli hosts a small lab space for companies interested in applications of functional components in non-foods – such as cosmetics etc.

According to the impression I got from the visit Polli lab is open-minded for different collaborations! Hope that our lab can do some collaborative project soon as we don’t have SFC instrumentation ourself yet and I would also encourage others to investigate the possibilities for collaboration with such nicely equipped centre.

Website of Polli lab: http://www.plantvalor.ee/index.php/home/

Motivation day!

Students I supervised last school year gave me a rafting trip with them from my birthday in May and on this Friday we vent to Võhandu rive for this trip. Altogether we passed 20 km containing both quite slow flow parts but also some cascades. Slow parts, though not that adventures, taught us some practical team work.

Mari, Me, Asko, Hanno and Piia (Jaanus is taking the picture).

In the end of the day we had a very nice grill and sauna at Mari’s place. For some strange reason we had agreed with Jaanus for a challenge in plank which ended up with everyone planking and finding out their best. Now we agreed to do it again on autumn seminar with the aim of improving personal best.

Hanno, Asko, Jaanus, Piia, Me and Mari.

It was a great day, thank you! Already looking for a next motivation day!

Optimizing or troubleshooting LC?

Hi!

Today I would like to introduce you to two books that I find very valuable and that can be freely downloaded from the internet. The “Five keys to successful LC methods” and “Controlling selectivity in reversed-phase LC” are collections of articles published in LC/GC in the section “LC Troubleshooting” by John W. Dolan. It’s useful whether you are a beginner learning on you own or a specialist working with LC every day.  I can assure that even the latter will find something refreshing in these writings. And of course I have to admit I am a big fan of John W. Dolan. His columns in LC/GC are both a good study material but often also a fascinating detective story for an analytical chemists (eg this one here: http://www.chromatographyonline.com/calibration-problems-case-study-1). 
Both books are freely available from the LC/GC homepage (http://www.chromatographyonline.com/lcgc-ebooks).

Here I would also like to come back to one of J.W. Doles thoughts that has really influenced me. I think everyone working with more than one compound or with matrix containing various stuff, have found themselves stuck with figuring out the best gradient to fit the resolution and speed desired. And of course this perfect gradient needs to be figured out fast to not waste any precious analyses time. Well, one really simple but hard to do thing to keep in mind is: First things first. Don’t mess with the middle part of your LC gradient before you have a needed separation for the early eluting peaks. Firstly, this is really pointless – changes in the beginning will very likely influence resolution in the middle part as well. Secondly, it just waists extra time – you will most probably have to do this once again after you have made the necessary changes in the beginning of the gradient. I know from my own experiences that it is hard to stick to this rule but it sure pays off! I would even extend this not only to LC gradient but also to other fields, eg sample prep – your solution composition most probably is influenced by the dissolving, pH regulation, etc steps you carry out in the beginning of the sample prep. Therefore before you start working out your SPE you should know in what form (including solvent etc your sample is by this stage. Of course, here this is even harder, as if SPE is not working at all (eg analyte flushes through the cartridge during sample introduction) it is also hard to optimize earlier steps (unless you can make injections without SPE).

For practitioners: do you need weighted linear regression?

In my statistics course, similarly to I guess all other teachers concerned in calibration, I teach that for instrumental analyses weighted linear regression should be used. Why? Non-weighted linear regression (the one we can use with LINEST, SLOPE and INTERCEPT in excel) assumes same signal precision (repeatability standard deviation in other words) for all concentrations in the calibration range. For instrumental analyses however the relative standard deviation of the signal is usually (there are some specific instruments where this does not apply) nearly constant over concentrations used.

Veronica Meyer¹ published in LC/GC a good simulation aiming to show how much results are influenced by either using or not using weighting in linear regression.

Their simulations effectively demonstrate that advantages of weighting are observed only if all following four things happen simultaneously:

1. Absolute repeatability standard deviation is not constant over given concentration range.

2. The calibration range is very wide.

3. Calibration points are distributed equally over the calibration range.

4. Sample result is at the lower end of the calibration range.

For example if calibration points 2, 1000, 2000, 3000 and 5000 units were used for calibration and the sample with actual concentration of 2.0 units was measured unweighted regression yielded answer of 8.3 but weighted resulted in 1.95 units. This simulation only included random errors.

On the other hand if a narrower calibration range – around one order of magnitude – would be used there is no significant difference in using or not using weighting.

So what to do if you are in the lab doing your actual analyses? I’d suggest you to prepare at least 5 point approximately equally spaced standard solutions for each order of magnitude your method needs to work in. For example if you samples concentrations may range from 10 – 1000 ppb I’d suggest following solutions: 10, 25, 50, 75, 100, 250, 500, 750 and 1000 ppb.

After analysing these solutions I would break up this calibration into two parts 1) 10-100 ppb and 2) 100-1000 ppb. This way you can assure that the highest concentrations on the calibration graph do not influence the accuracy of the samples in the lower end.

Good calibration!

¹ V. Meyer Weighted Linear Least-Squares Fit — A Need? Monte Carlo Simulation Gives the Answer, LC/GC 28 (2015) 204-210.

Up-to-date analytical methods introduced to school children in 47th International Chemistry Olympiad in Baku, Azerbaijan

From 20^th to 29^th of July 47^th International Chemistry Olympiad (IChO) was held in Baku, Azerbaijan. All together 290 form 75 countries solved 3 practical and 8 theoretical tasks. This Olympiad was definitely one of the hardest in IChO history, most probably being hard to solve for a masters student not only for high school students.

The tasks given to students were very versatile introducing students both to history of Azerbaijan chemistry industry but also to up-to-date methods. One of the practical tasks given to student’s concerned estimating drug content in medicine based on initial rates. The drug Diclofenac was oxidized with KMnO₄ and the spectral change was followed at 525 nm (Figure below) in the thermostated conditions. 

The content was calculated based on a four point calibration graph (initial rate vs concentration). For solving this task students were given (see a photo below) miniaturized photometer, thermostat, cuvette and a magnetic stirrer. The photometer and thermostat were directly controllable with a laptop. Student carried out data treatment in Excel.

I find this problem being a true success as this really introduces young students with interest in chemistry to the analytical methods used today in labs.

For more tasks see http://icho2015.msu.az/

Why I start such a blog?

I started writing this blog to share with you some fascinating stuff I come across every once in a while. I try to cover not only the research of me and my co-workers but also other fabulous scientific papers. Also I give some practical tips concerning statistics, optimization of analytical methods (especially LC and MS) as well as validation. I hope to give something for everyone – for a fellow scientist, practitioner and for just a science fan.