The ESTCube-1 satellite was successfully launched early in the morning of 07.05.2013! Some hours later on the same day it was officially announced that the satellite works. Three AMS students (Kaspars Laizans, Martynas Pelakauskas, Mykola Tverdokhlib) are participating or have participated in the project. See more at the ESTCube-1 Facebook page.
_
_
_END_
Hydrogen bond (HB) is by its importance a unique chemical phenomenon in nature and has been widely studied from almost any possible viewpoint. HBs have an enormous role in the structure (proteins, nucleic acids, cellulose fibers, etc) and functionality (enzyme catalysis, ligand-receptor complexes, etc) of all forms of life as well as a countless number of supramolecular systems. Computational prediction of HB is of high interest both for rationalizing existing and developing new chemical and biochemical systems and processes. A comprehensive study of modeling HB with the COSMO-RS computational method has been recently carried out at UT Chair of analytical chemistry (ChemPhysChem, 2013, 14). The method displayed mixed behavior, being quite successful with some systems but failing with others.
Q: What is the connection here with measurements?
A: A direct one. The level of success of the computations was assessed by comparison with measurement results of hydrogen bond formation equilibrium constants. And, surprisingly, it turned out that a large part of data on HB formation constants in the literature was unusable because of inconsistrencies and lack of any information characterizing the uncertainty of the values. The values from different groups sometimes varied by up to an order of magnitude (!). Such doubtful datasets of course were left aside when carrying out the evaluation.
This work nicely proves the importance of good measurement science also for theoretical chemistry: it is not possible to develop and improve theoretical computation methods if teh obtained results cannot be compared to accurate measurement results.
_END_
An important direction in making measurement instruments is making them simpler, cheaper and accessible to many people. An interesting development in this direction has been made at SYKE (the Finland Environmental Administration): the Secchi3000 Turbidity analyser, in which a standard mobile phone camera serves as the measurement instrument.
Secchi3000 was developed to be a low cost and simple operation tool for water quality measurements. The objective was to offer it also for non-experts and citizens interested in water quality issues. Performing measurement with Secchi 3000 is simple: The user fills the Secchi3000 container with water from a lake, river or sea, places the measurement structure in the container and takes a photograph with a mobile phone through a hole in the lid of the device (Figure on the right). The photograph is taken with an application called EnviObserver (developed by VTT, Finland). The application sends the photograph to a server together with metadata such as the location of the measurement. At the server the photograph is analysed with an algorithm, which finds the target areas from the picture and computes water quality parameters based on the brightness values of the target areas. Finally, the results are sent back to the user’s mobile phone and stored in data bases.
For more information please download the poster about the Secchi3000 water turbidity analyser.
_END_
During 17-22.02.2013 The first Analytical Chemistry Winter school “Novel analysis methods”, organized by the St. Petersburg’s State University, took place near St. Petersburg. Ivo Leito participated in the event and gave a short lecture about Liquid chromatography tandem mass spectrometry with the electrospray ion source (LC-ESI-MS/MS) as a tool in trace contaminant analysis. The lecture presented the difficulties in connecting LC to MS, described electrospray (ESI) ion source as the most widely used intrerface for connecting LC and MS, briefly explained the multidimensional information obtainable from LC-MS experiment and finally reviewed the benefits of tandem mass spectrometry (MSMS or MS2) detection in trace contaminant analysis as opposed to simple MS detection.
As real-life examples of using liquid chromatography tandem mass spectrometry in analysis of traces of contaminants and bioactive compounds, see for example the following:
– Determination of pesticide glyphosate in cereals LC-ESI-MSMS (Rapid Commun. Mass Spectrom. 2011, 25, 3252–3258)
– Analysis of seleno amino acids selenomethylselenocysteine and selenomethionine by LC-ESI-MS/MS with diethyl ethoxymethylenemalonate derivatization (Analyst 2011, 136, 5241-5246)
– Analysis of five pesticides (methomyl, thiabendazole, aldicarb, imazalil, methiocarb) in five fruit/vegetable matrices (tomato, cucumber, apple, rye and garlic) using LC/MSMS with electrospray ionization (Analytica Chimica Acta 2009, 651, 75–80)
Ivo Leito also gave a short overview of the Applied Measurement Science programme.
_END_
Measurements of acidity and basicity of strong and superstrong acids (superacids) and bases in organic solvents is among the core research topics at the UT Chair of Analytical Chemistry. In a recent publication (J. Phys. Org. Chem. 2013, 26, 162-170.) the behavior of a number of acids (including some superacids) was examined in three solvents (water, acetonitrile, 1,2-dichloroethane) and in the gas phase. Acidities (pKa) of a number of different acids including the well-known superacids trifluoromethanesulfonic (triflic) acid, HBr, HI, bis-trifylimide (Tf2NH), etc as well as weaker acids (HCl, acetic acid, phenol) etc are examined in the above mentioned solvents. pKa of superacids are not easy to find in literature. Trends of acidity changes on moving from water to the gas phase deepnding on the on the nature of the acidity centre and the molecular structure are analyzed. The acidity orders are different in water, AN, DCE and the gas phase. In some cases – notably, the hydrohalogenic acids HCl, HBr and HI – the differences are dramatic. These three acids are among the strongest known acids in water but have modest acidity in the gas phase. In contrast, 9‑C6F5‑Octafluorofluorene, a weak acid in water (approximately of the strength of phenol) is quite strong acid in the gas phase, beating any of the hydrohalogenic acids.
It is demonstrated that the decisive factor for behavior of the acids when transferring between different media is the extent of charge delocalization in the anion and that the recently introduced WAPS parameter in spite of its simplicity enables interpretation of the trends in the majority of cases. The acidity data are given in the Table below.
Table of pKa valuesa of acids in different solvents from J. Phys. Org. Chem. 2013, 26, 162-170.
Acid
H2O
MeCN
DCEb
GP
GP
pKa
pKa
pKa
pKa
GA
Fluoradene
11.1
23.90
12.5
238.2
324.9
Para-Toluenesulfonamide, 4-CH3-C6H4-SO2-NH2
10.21
26.87
15.6
244.9
334.0
9‑C6F5‑Octafluorofluorene
10.1
18.88
3.8
220.4
300.6
Phenol
10.00
29.14
19.6
251.0
342.3
(C6F5)2CHCN
9.5
21.10
10.3
229.0
312.4
C6F5CH(CN)COOEt
5.89
17.75
7.6
229.8
313.5
2,4-Dinitrophenol, 2,4-(NO2)2-C6H3OH
4.09
16.66
4.7
226.2
308.6
(CF3)3COH
5.40
20.55
9.2
237.5
324.0
Acetic acid, CH3COOH
4.76
23.51
15.5
250.1
341.1
(4-CF3-C6F4)2CHCN
4.4
16.13
6.0
221.5
302.1
4-NO2-C6H4-CH(CN)2
2.3
11.61
0.3
219.6
299.5
Saccharin
1.80
14.57
5.5
231.6
315.9
Picric acid, 2,4,6-Trinitrophenol
0.40
11.00
0.0
219.2
299.0
(4-NO2-C6H4-SO2)2NH
<-1
8.19
-3.7
213.4
291.1
(CF3SO2)3C6H2OH
-2.0
4.48
-6.4
208.4
284.2
(C2F5SO2)2NH
<-2
-0.10
-12.3
208.0
283.7
(CN)3CH
-5.1
5.1
-6.5
216.1
294.8
Triflic acid, trifluoromethanesulfonic acid, CF3SO2OH
-12
0.70
-11.4
214.8
293.0
Hydrochloric acid, hydrogen chloride, HCl
-7
10.30
-0.4
240.5
328.1
Hydrobromic acid, hydrogen bromide, HBr
-9
5.5
-4.9
233.3
318.3
Pentacyanopropene
-9.02
-2.80
-15.3
195.9
267.2
Hydroiodic acid, hydrogen iodide, HI
-9.5
2.8
-7.7
226.7
309.2
a There are numerous comments and details to these values. Please see the original article J. Phys. Org. Chem. 2013, 26, 162-170. for details and comments. b pKa values relative to picric acid in 1,2-dichloroethane.
_END_
Amer Jamil Aref Al-Malahmeh from Jordan successfully defended his master thesis on January 15, 2013. The title of the thesis was “Methodological development and validation of Sample treatment and Source preparation procedures and Liquid Scintillation counting measurements for Determination of 226Ra in Drinking water”. 226Ra is a potentially dangerous radionuclide for people using ground water as drinking water. A large number of different influencing factors were tested and evaluated in the thesis and a serious uncertainty budget was compiled, which can be of high interest to scientists working in the area of radionuclide determination. The thesis is remarkable also because it was defended four months (!) in advance of the deadline.
_END_
On Saturday, Dec 15, 2012, the Autumn semester master’s seminar 2012 of the AMS programme was concluded with presentations from students.
Most of the presentations were based on the master’s thesis topics of our students. As is typical for our interdisciplinary programme, the topics were diverse, ranging from determination of radium in water to artificial molecular receptors, from universal pH scale to building a student satellite. Here is a short (and not exhaustive) list of the areas in which our students do their master’s projects:
_END_
Should you have interest in any of these (or other) topics you are welcome to contact Ivo Leito.
Before the seminar, a questionnaire (anonymous) was distributed to the students addressing the AMS programme. The questions were about the usefulness of the programme in finding a job related to measurements or chemical analysis, about the general organization of the programme, quality of teaching, etc. The presentations were followed by a discussion of the responses. Many constructive comments and suggestions for improvements were received from the students.
It is very pleasant, however, that the overall evaluation of the programme by the students was very high, both in terms of the quality of teaching and in terms of competitiveness of the graduates on the job market.
_END_
Liquid chromatographic separation of basic analytes is often hampered by problems, such as insufficient retention, wide and asymmetric peaks, etc, especially if carried out at acidic pH. Many modern HPLC coulmns can stand pH values up to 10 without problems and separation at a higher pH is often a good approach for liquid chromatographic separation of basic analytes, such as different amines. Unfortunately, the choice of buffer systems in the range of pH 7-10 suitable for LC/ESI/MS work is very limited. The main requirement for the electrospray ionization mass spectrometry is that besides suitable pH all the components of the buffer system should be volatile. This immediately excludes phosphate, carbonate, borate, etc buffers. On the other hand, the buffer should not compete with the analytes in the electrospray ionization process. This excludes most organic bases. The ammonia/ammonium acetate or ammonia/ammonium formiate buffers are the most used ones. Nevertheless, also use of these buffers and mobile phase pf pH aroun 9 often results in less than ideal separation and peak shape. Thus new LC/MS-compatible volatile buffer systems would be highly welcome.
Karin Kipper from UT Institute of Chemistry has made a significant contribution in this field by introducing two new buffer compounds, two fluoroalcohols – 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) and 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol (HFTB) (Journal of Chromatography A, 2011, 1218, 8175–8180). She has found that these compounds offer interesting possibilities to adjust retention behavior of different analytes by using high pH values (ammonia is used for pH adjustment) and expand the currently rather limited range of ESI-compatible buffer systems for basic mobile phases. Good separation of different compounds was observed with excellent peak shape. The fluoroalcohols did not suppress the ionization of the analytes in the electrospray source and for several analytes ionization enhancement was observed. Thus, these compounds are suitable for electrospray mass spectrometry.
All trends in retention of the acidic and basic analytes can be interpreted by the following model: the neutral fluoroalcohols are quite strongly retained by the stationary phase whereas their anions are less retained, thus their amount on the stationary phase is dependent on mobile phase pH; the anions of the fluoroalcohols form ion pairs in the mobile phase with the basic analytes; the fluoroalcohols on the stationary phase surface compete with acidic analytes thereby hindering their retention; the fluoroalcohols on the stationary phase bind basic analytes thereby favoring their retention.
The suitability of these fluoroalcohols as buffer components for LC/ESI/MS analysis has been verified on the example of simple organic compounds (bases, such as amines, pyridines, anilines) as well as several antibiotics – three fluoroquinolones: ciprofloxacin, norfloxacin, ofloxacin; and two sulfonamides: sulfadimethoxine, sulfamethoxazole (Analyst, 2011, 136, 4587–4594).
We hope that this novel approach will eventually gain popularity and we welcome any feedback on its practical use.
_END_
A new software package for measurement uncertainty calculation called MUkit (shortcut from: Measurement Uncertainty kit) has been recently made available by SYKE, the Finnish Environmental Administration. This is the first software package that offers direct support for laboratories in measurement uncertainty evaluation according to the increasingly popular Nordtest approach of measurement uncertainty estimation.
The MUkit software is freeware and is available for download free of charge from the SYKE ENVICAL website. The capabilities of the software are described in the users manual available from the same website as well as in the recently published article Software support for the Nordtest method of measurement uncertainty evaluation. Teemu Näykki, Atte Virtanen, Ivo Leito Accred. Qual. Assur. 2012.
Any feedback on the use of the software is most welcome!
_
_END_
Electrospray ion source (ESI) is the most used ion source type for connecting liquid chromatography (LC) with mass spectrometry (MS) due to its robustness and possibility to analyze a wide range of analytes. ESI is a very good LC/MS ion source but it still has two major shortcomings. Firstly, ESI is in general not efficient in generating gas-phase ions (meaning, the large majority of the analyte molecules pass the ion source without being detected). Secondly, ESI is susceptible to the so-called matrix effect – decrease of the analyte response in the presence of compounds co-eluting with the analyte. These drawbacks lead to lowering the sensitivity and increase of the risk of possible false-negative results.
Anneli Kruve from UT Chair of Analytical Chemistry has come up with an original idea how to improve the sensitivity of an ESI source and make it less susceptible to the matrix effects. The essence of the idea is to modify the nebulizer (the key component of an ESI source) by adding an additional capillary directing the nebulization gas right into the stream of solution (the thin innermost capillary on the image). The prototype of this ion source has been built (see the image) and experiments have shown that this design offers significantly enhanced ionization efficiency compared with the classic nebulizer design and leads to improved sensitivity (by three to 10 times) and decreases the detection limit, on an average 10 times. The patent application of this development has been filed and a communication has been published in J. Am. Soc. Mass Spectrom. (2012).
Recent studies have shown that the matrix effect in the ESI source mostly arises from the competition of ionized analytes and matrix compounds for the droplet surface. It is expected that by more effective nebulization the net surface area of the droplets increases and thus the competition decreases leading to decrease or elimination of the matrix effect. Testing of this hypothesis is currently in progress.
The gain in ESI sensitivity may open up new horizons in different fields of LC/ESI/MS application. It may become possible to detect different marker molecules at very low levels in complex biological matrixes in biochemical and medical analysis, possibly leading to e.g. early discovery of diseases; it may become possible to determine the background concentrations of organic pollutants in environment, which is very important for understanding and modeling their behavior in the environment; etc.
(Image by Ave Saluvee)
_
_END_
On August 31, 2012 Irja Helm successfully defended her PhD Thesis High accuracy gravimetric Winkler method for determination of dissolved oxygen at Institute of Chemistry, University of Tartu. The essence of the work is development of a highly accurate gavimetric Winkler titration procedure for determination of dissolved oxygen content in calibration medium for optical and amperometric dissolved oxygen sensors.
Dissolved oxygen (DO) content in natural waters is a very important parameter. Recent studies show decrease in DO content in several areas of world oceans. Processes leading to this decrease are not completely understood and it is very important to be able to measure DO content very accurately for studying the dynamics of these processes. Amperometric and more recently also optical oxygen sensors are widely used in DO measurements. These sensors need calibration and therefore solutions with accurate DO concentration are necessary. And this is where Irja’s method will be very useful.
_
_END_
On 31.08.2012 the introductory meeting for first-year AMS students was held. Sergei Jurtšenko gave overview of the AMS programme, timetable of autumn semester 2012 and some practical aspects of living and studying in Tartu. The PDF file of this presentation is available for download from here.
_
_
_
_END_
Klodian Dhoska, graduated from AMS in 2010 shared his thoughts about how the programme has influenced his life during the last two years:
“Experience at Applied Measurement Programme has given to me a very good career. I am technical expert at Albanian Accreditation Directory, Head at Mechatronics Department on private University in Tirana, part-time lecturer at Polytechnic University of Tirana and in the end I am accepted as a full time doctoral student at Tallinn University of Technology. You don’t need to search for a good career because the career is following a succesful AMS programme at University of Tartu.”
_
_
_
_END_
The MSC Summer school finished on Jul 27, 2012. Kristjan Haav, one of the participants (from the AMS programme, University of Tartu) shared his impressions.
Ivo: What would you single out as the top experiences in the summer school?
Kristjan: From the professional viewpoint it was the experience of being the leader of our team “Magus Jook Laboratory” in the Student contest. I was elected leader by our group because it turned out that I had somewhat deeper knowledge about analytical chemistry than my groupmates. I had no similar leadership experience prior to the summer school and managing the work of an international group was quite a challenge. Eventually it worked out quite well – our team got 24 points out of 25 for the student contest. From entertainment point of view the top experience was certainly the surfing day on the ocean coast.
Ivo: OK! So, I understand that the knowledge and skills that you have obtained from the first year of AMS were sufficient for participating in the Summer school?
Kristjan: Yes. It was actually quite pleasant realize how many valuable things we have learned.
Ivo: What is your overall impression of the summer school?
Kristjan: It was much more challenging and exhaustive than I thought. It was two weeks of serious studying, both in theory and in practice. And it is not over yet – we still have homework to complete. I would say that especially the practical assignments at the Summer school were very interesting and useful.
_
_END_
As a nice counterbalance to the serious and challenging programme of the summer school last weekend there was a surfing outing at the summer school.
All participants had the possibility to try surfing in the Atlantic Ocean under the guidance of professional instructors. It seems that they had a lot of fun!
_
_
_END_
On Monday, July 16, 2012 the fifth Measurement Science in Chemistry International Summer School started in Fatima (Portugal). In this edition, 48 students from thirteen countries participate. The dense and challenging programme will give the students opportunities to learn and practice almost every metrological aspect of analytical chemistry.
Topics, such as Validation of chemical analysis procedures, Statistical basis of calibration, Traceability in chemical analysis, Measurement Uncertainty, including the Alternative Approaches for the Quantification of Measurement Uncertainty, ISO 17025, Sampling and sample preparation in food and environmental analysis, Customer-analyst interactions are included in the programme.
Efforts are made to make the summer school more interactive (as opposed to listening to lectures). This is done via the student contest/game, accreditation visit to a real lab and numerous group work sessions.
More information can be found at the MSC Website.
_
_
_
_END_
Alda Andersone from Latvia defended her master thesis on June 11, 2012. The title of the thesis was “The stereoselective synthesis of 2,2,5-trisubstituted tetrahydrofurans, oriented to the preparation of lilac aldehydes and alcohols”.
The thesis was awarded the highest mark “A”. Alda talks about the thesis: “I prepared my master’s thesis in the organic chemistry field. The main goal of my work was to find out the best synthesis scheme to synthesize as pure as possible stereoisomers of 2,2,5-trisubstituted tetrahydrofurans. Main goal was achieved, 98% enantiomerically pure 2,2,5-THF enantiomer was synthesized”.
Here are some of Alda’s comments about University of Tartu and the AMS programme:
University of Tartu provided me with rich knowledge in theoretical and practical base. We had lots of practical trainings and interesting and useful information in lectures. And it was very useful that some information was overlapping between lectures – great possibility to repeat material.
During study time I was working in the UT Institute of Technology in organic chemistry laboratory. And I would like to thank PhD Lauri Vares for accepting me in his research group. During master’s thesis work up time I was supervised by Ilme Liblikas, the best supervisor I ever had. Thank You, Ilme!
Leaving University of Tartu with master’s degree in my pocket I feel much richer – I had a great opportunity to study in international programme, improve my English and make lots of new friends from different countries all over the world.
I would like to thank prof. Ivo Leito for being such a great leader, and University of Tartu over all for hosting me.
In the future I am definitely planning to use my knowledge in Chemistry and Applied Measurement Science. And probably at some point I will get PhD.
_
_END_
Hanno Evard defended his master thesis on June 11, 2012. The title of the thesis was “Study of paperspray ionization and its possible applications”.
The thesis was awarded the highest mark “A”. Hanno talks about the thesis: “My master thesis topic was about studying a new ionization method for mass spectrometry – Paperspray Ionization. In the course of the study I got the possibility to work with different mass spectrometers including an FT ICR mass spectrometer. As it was the first time in University of Tartu to study this ionization method the work was very complicated. However with the help of my supervisor and other staff in the Chair of Analytical Chemistry the working was easy and fun. I found in the course of the thesis that the new method can be used to obtain information about composition of papers and to identify pesticides from citrus fruits bought from a supermarket. I will be working further with Paperspray Ionization in the course of my doctoral studies”.
Here are some of Hanno’s comments about University of Tartu and the AMS programme:
The past two years while studying in the Applied Measurement Science programme have been very interesting and fun. University of Tartu gives a wide field of education and strong practical experience on the studied subject. The teachers are friendly and ready to help with any problems that students might have. Moreover they are at the top of their fields and therefore the most qualified to teach the subjects. The laboratories and lecture halls are new and well equipped. Students have the possibility to use and study complex and expensive equipment. The programme gives you a good opportunity to meet people from all around the world.
_
_END_
Seven AMS master’s candidates successfully defended their theses on June 11, 2012. Congratulations!
The PDF files of all the theses are available for download from here.
(See at the end of the list: Hanno Evard, Karlis Andersons, Alda Andersone, Eyüp Zorla, John Can Blackburn, Mykola Tverdokhlib, Juliia Demchuk).
_
_
_END_
On May 21-22, 2012 a workshop Validation, Traceability, Measurement Uncertainty: the Challenges for the 21th Century Analysts took place in Berlin. This workshop focused on the relationship between method validation, traceability and measurement uncertainty in various fields of quantitative analytical measurements. In addition to lectures there were two workshop sessions devoted to discussions about the practical problems of validation of analytical procedures, establishing and demonstrating traceability and estimating measurement uncertainty.
Ivo Leito from University of Tartu participated in the workshop with the presentation Using method validation and performance data for estimating measurement uncertainty.
_
_END_
