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.

More information can be found in the post CGPM votes unanimously to change the SI by Dr Steve Ellison at the Eurachem website.

(Image: Wikipedia)

 

On Nov 05, 2018 Ivo Leito gave a presentation Unified pH about the pan-European research network of fundamental pH Research UnipHied (www.uniphied.eu) at the 7th Baltic Electrochemistry Conference organized by the University of Tartu.

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 chromatograpy, 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.

 

On Oct 26, 2018 Ivo Leito gave presentation titled Analytical chemistry education activities at University of Tartu at the EcoBalt 2018 conference in Vilnius (Lithuania).

The presentation contains information about the on-line courses LC-MS Method Validation and Estimation of Measurement Uncertainty in Chemical Analysis, as well as the recently published tutorial reviews (Validation I, Validation II, LoD I, LoD II) that form the basis of the LC-MS Method Validation course.

The presentation also addresses the international master’s programmes Applied Measurement Science and Excellence in Analytical Chemistry at University of Tartu.

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”.

 

Validation_of_LC-MS_Methods_Online_CourseWe are glad to announce that the third edition of the online course LC-MS Method Validation is open for registration at the address https://sisu.ut.ee/lcms_method_validation/ !

The course will be offered as a Massive Open On-line Course (MOOC) during Nov 27, 2018 – Feb 08, 2019.

This is a practice-oriented on-line course on validation of analytical methods, specifically using liquid chromatography-mass spectrometry (LC-MS) as technique, mostly (but not limited to) using the electrospray (ESI) ion source. The course will also be of interest to chromatographists using other detector types. The course introduces the main concepts and mathematical apparatus of validation, covers the most important method performance parameters and ways of estimating them. The course is largely based on the recently published two-part tutorial review:

The course materials include lectures, practical exercises and numerous tests for self-testing. In spite of being introductory, the course intends to offer sufficient knowledge and mathematical skills for carrying out validation for most of the common LC-MS analyses in routine laboratory environment. The real-life analysis situations for which there are either examples or self-tests are for example determination of pesticides in fruits and vegetables, perfluoroalkyl acids in water, antibiotics in blood serum, glyphosate and AMPA in surface water, etc. It is important to stress, that for successful validation practical experience – both in analytical chemistry as such and also specifically in validation – is crucial and this can be acquired only through hands-on laboratory work, which cannot be offered via an on-line course.

Participation in the course is free of charge. Receiving digital certificate (in the case of successful completion) is also free of charge. Printed certificate (to be sent by post) is available for a fee of 60 EUR. Registration is possible until the start of the course. The course material is available from the above address all the time and can be used via web by anyone who wishes to improve the knowledge and skills in analytical method validation (especially when using LC-ESI-MS).

 

During 29.09-10.10.2018 the UT Institute of Chemistry has been hosting visiting scholar, Prof. Narendra Nath Ghosh from the Birla Institute of Technology and Science Pilani, K K Birla Goa Campus (India). He conducted an intensive course Nanomaterials and Nanotechnology and their Applications in Analytical Chemistry.

This lecture series started with introduction to nanomaterials and nanotechnology, the origin of nanotechnology and nanomaterials, and how and why the properties of nanomaterials are different from bulk materials. It then developed to cover design of a variety of nanostructured materials, their preparation techniques and different analytical instrumental methods for structural characterization of nanomaterials. Finally, a significant amount of time was devoted to the use of nanomaterials in different analytical techniques, especially in sensor applications and applications of these sensors in real life (detection and estimation of different types of analytes such as glucose, H2O2, metal ions, etc and how these nanosensors can be used for health monitoring, food quality monitoring, and environmental monitoring).

Altogether 15 students (out of them 7 AMS students) participated in the course and their feedback was very positive.

Prof. Ghosh is the Associate Dean, International Program and Collaboration at the Birla Institute of Technology and Science Pilani, K K Birla Goa Campus. His research interests embrace development of new and novel chemical methodologies for preparation of nanomaterials, mesoporous materials and nanocomposites, as well as applications of nanomaterials in catalysis, sensors, separations, microwave absorption, supercapacitor etc.

(Photo by Ivo Leito: Prof. Ghosh, in the middle, with students)

 

Recently the Analytical chemistry group of University of Tartu participated in a cutting-edge research endeavor: characterizing the acidity of some extremely efficient strongly acidic organocatalysts. In the case of the Mukaiyama aldol reaction the best of them (1) worked at low ppm to sub-ppm level, (2) gave excellent yields and (3) high enantiomeric selectivity as well as (4) turnover numbers (TON numbers) of hundreds of thousands (Nature Chemistry 2018, 10, 888-894).

The extent to which these four features occurred together in the same catalyst was so remarkable that the results were published in one of the most prestigious journals in chemical sciences: Nature Chemistry.

The extremely demanding acidity measurements were performed by Dr Karl Kaupmees using the unique non-aqueous acid-base chemistry facility that the group is running. The whole research project was led by the group of professor Benjamin List – a worldwide known guru in the field of strongly acidic catalysts working at the Max-Planck-Institut für Kohlenforschung.
These results are expected to open new avenues in development of powerful new organocatalysts.

(Photo by Andres Tennus: Karl doing acidity measurements in a glovebox under anhydrous conditions)

This week is the first study week for the new students of Applied Measurement Science and EACH Erasmus Mundus Joint Programme. Altogether 27 students started their studies. This is the largest joint number of students of these two programmes.

As a result of the rather large number of students, the countries of origin of the students are also very diverse: Vietnam, Philippines, Brazil, Estonia, Nepal, Thailand, Peru, India, Netherlands, Fiji, Albania, Nigeria, Mexico, Kazakhstan, Egypt, Ukraine, Pakistan and Turkey. And for the first time all six inhabited continents are represented!

During the introductory meeting on Monday 03.09.18 an overview of both programmes was given (see the slides) and a large number of questions were asked and answered, accompanied by tea/coffee and cake. The session ended with an entertaining “get-to-know-each-other” game organized by the tutor Kristi Palk (far left on the photo).

We wish successful studies to all new students!

 

On August 10, 2018 the master thesis defence session of the second of the EACH programme, the “sister programme” of AMS, took place at Åbo Akademi University (AAU)! Kenneth Arandia, Changbai Li, Jay Pee Oña and Jayaruwan Gunathilake Gamaethiralalage successfully defended their master’s theses. (first row on the photo, left to right)

Congratulations to all of you!

The defence took place in front of an international jury – Tom Lindfors (Finland), Patrik Eklund (Finland), Johan Bobacka (Finland), AdrianaFerancova (Slovakia/Finland), Ivo Leito (Estonia), Hanno Evard (Estonia). (second row on the photo, right to left, Hanno participated via Skype)

Most of the defended theses focused on development and applications of advanced electrochemical sensing devices – preparation of all-solid-state sensors, solid state reference electrodes, calibration-free potentiometric analytical devices, etc.

Most of the students who defended their theses have already secured either a PhD position or a job in industry.

(Photo: Jayaruwan Gunathilake)

 

A new paper on ancient dietary practices was recently published by our group (led by Dr. Ester Oras) in the Journal of Archaeological Science: “Social food here and hereafter: Multiproxy analysis of gender-specific food consumption in conversion period inhumation cemetery at Kukruse, NE-Estonia”.

We demonstrated the fruitfulness of multiproxy dietary analysis combining plant microfossil, human bone stable isotope and pottery related organic residue analysis. The results reveal that even 800 years ago men and women had different dietary habits: men preferred fish and higher trophic level terrestrial animals (e.g. pork), whilst women declined towards ruminant carcass (a nice steak!) and dairy products.

The paper is one of the few of its kind illustrating ancient food consumption as a highly social phenomenon, and setting an example for microscale dietary analysis in the future.

On Saturday 21.07.2018 The MSC Euromaster Summer School 2018 (Tallinn, Estonia) finished. It was the 11th summer school of the Measurement Science in Chemistry consortium. The hallmark of the MSC Summer schools is “learning by doing” and combining learning with fun, meeting new people and sharing experience. The feedback from the Tartu participants is below and it indicates that organizing these Summer schools it is worth the effort!

 

 

 

Angelique Dafun:
MSC Summer School is a great experience to learn and have fun at the same time. It encompasses intensive learning and practical applications of metrology and accreditation that are significant for an analytical chemist in a “learning through play” way. It is an opportunity to gain knowledge from the experts in the field and to learn about the culture of people from different parts of the world. The schedule is tight and a little bit tiring but having an amazing group of people made it really rewarding. With other Filipinos, we dream of having this kind of summer school in our country someday in order to improve our system in analytical measurement.

 

 

Nikola Obradović:
The MSC Summer School is a great opportunity for all those who want hands-on experience in operating a laboratory under ISO/IEC 17025. Through many theoretical and practical exercises, the participant of this course is led through the whole process of method validation. But, the school is not all about studying. There is much networking going on here, with people making friends and partnering up to do new and exciting projects. Thus, for many, the end of the Summer School marks the start of a whole new chapter in their lives. As the moto of school states: “To mesure is a pleasure!”

 

 

Mark Justine Zapanta:
The MSC Summer School provides a great opportunity to deepens one’s knowledge and understanding of measurement science and accreditation in a fun and exciting way. The “learning through play” theme of the School allows participants to apply theories by making them think, design, implement, and evaluate their approach to answer an analytical problem. Outside the walls of the classroom, participants get to broaden their social network as the School is highly diverse with people coming from different cultures and backgrounds and it is the cultural exchange that adds more flavor and spice to the summer school. Attending the MSC Summer School is truly a one of a kind experience!

 

 

Ernesto Zapata Flores:
Well, it was more than the expected, I mean I met people from different countries around the world, from Ghana, Myanmar, Ireland, Belgium, Portugal, etc. I made a lot of friends. By the other side, there were some topics that I had learned at the University of Tartu, but others were completely new to me. The Professors had an excellent attitude towards us. It was an extremely good experience, the group work gave a lot of stress but it was exciting because of sharing points of view with people from different backgrounds and countries contributed to enrich not only the project but my own knowledge.

 

 

 

On Sunday 8th July, 38 students from 17 countries made their way to the beautiful city of Tallinn. The round of introductions already told us a lot about the individuals, much more than they intended. On Monday 9th July, armed with a little information and lots of things to think about, from the earlier sessions, the students set off, in their teams, to collect sea water samples (Photo on the left). All managed to complete the task but for some the waters were muddied, in more ways than one. Finding out the next day, Tuesday 10th, that salinity measurements are not trivial was a rich learning experience and shed light on many of the pitfalls awaiting the unsuspecting sampler/analyst.

These issues were then further embedded and clarified in various lectures (parts of the resource or process requirements of the ISO/IEC 17025:2017 namely chapters 7.1, 6.1 to 6.6, 7.1-7.8). Already on Tuesday evening the various laboratories (TEAM ONE, JCPT, K2Y, Cool Lab, Djam, We Click!, Elk Analytical, G.I.M.M., ISO CHEM and MONALU) had clearly defined roles and responsibilities for each of their staff. This was about to be tested when they got started on their measurements in the laboratory on Thursday afternoon, following a review of basic lab skills the day before.

Once in the lab the mixture of more and less experienced people really proved to be invaluable for both. It was really lovely to see the exchange of advice, with younger people sharing their intimate knowledge of software such as excel and what it can do and slightly older people providing perspective on what’s really important with respect to fitness for purpose decisions etc. (Ready for the lab! Photo on the right)

When the students had completed five full days of the summer school and were unwinding a little bit in Mektory’s lovely garden, sharing national food, drink, language tips, jokes, songs, (tall) tales from their countries, the idea of filming a mini ‘TV’ novella on Lab Safety was born. It just shows that free time is needed for creative juices to flow!

Saturday the 14th July was simply amazing. From learning that Estonians were Vikings too and what that actually meant, to learning some basic Viking skills (axe throwing and long bow shooting), followed by a hike to the magical Saula Springs, canoeing or long boat river excursion (Photo on the left) and finally ancient singing and dancing games (intermingled with dinner) left all feeling physically exhausted but mentally refreshed and ready for the World Cup Final on Sunday (preceded by a guided tour of Tallinn) and needless to say, another week of interactive learning.

 

On July 09, 2018 the 11th MSC Summer School started in the Mectory facility of the Tallinn University of Technology (Tallinn, Estonia).

Four students from the University of Tartu take part in the summer school. Three students are from the EACH programme: Angelique Dafun, Mark Justine Zapanta and Nikola Obradović. One student, Ernesto De Jesus Zapata Flores, is from the AMS programme. (Photo on the left, taken by Mark Justine Zapanta)

As in previous years, a core aim of the Summer school is teaching measurement science (metrology) topics related to analytical chemistry using active learning (“learning by doing”) approaches, as far as possible. Thus, efforts are made for increasing the share of discussions, hands-on work, teamwork. A key activity of the summer school is the contest of student teams (setting up virtual laboratories and interacting with customers), which tests their knowledge and skills in all areas of metrology in chemistry (Photo on the right).

We wish exciting and enjoyable Summer school to all participants!

 

On June 08, 2018 the master thesis defence of the second cohort of the EACH programme took place at Uppsala University! Thi Duong Bui, Anton Roshchin, Duc Khanh Tho Nguyen, Ruixin Huang, Alisija Prakapaitė, Kalliroi Sdougkou, Ajit Jung Karki and Snežana Đorđević successfully defended their master’s theses.

The topics of the theses embraced a wide area of modern biomed- and environmental analytical problems (MS imaging in biomedical research, LC-MS analysis of drugs in different matrices, evaluation of molecular markers for determination of efficiency in drinking water treatment processes, studies of photosynthesis, etc). All of them featured the use of highly sophisticated analytical instrumentation, such as high-resolution MS, imaging systems, etc. This choice of topics is largely directed by the world-famous biomedical analysis research direction at Uppsala University led by prof. Jonas Bergquist.

The average quality level of the theses was found to be very high by the defence committee members.

Congratulations to all of you!

(On photo from the left: Tho, Kalliroi, Alisija, Snežana, Ivo, Jonas, Duong, Ajit, Anton, Ruixin)

 

University of TartuIn a recent ranking of universities in the “New Europe” – the 13 countries that have become EU members since 2004 – carried out by the Times higher Education, the University of Tartu was ranked as No 1!

University of Tartu is followed by the Cyprus University of Technology and University of Cyprus. The Charles University in Prague is ranked fourth.

The list includes 53 universities in total and uses the conventional methodology of THE World University Rankings.

 

U_MOOC_Countries_of_Participants_2018On Tuesday, March 27, 2018 the web course Estimation of Measurement Uncertainty in Chemical Analysis was launched the fifth time as a MOOC (Massive Online Open Course)!

Currently more than 450 participants from 70 countries are registered! As was the case in the previous years, the majority of participants are from analytical laboratories. This once again demonstrates the continuing need for training in measurement uncertainty estimation for practicing analytical chemists.

The full course material is accessible from the web page https://sisu.ut.ee/measurement/uncertainty. As is usual, some developments and improvements have been made to the course material. in particular, the description of course organisatsion was improved; more explanations and examples were added on random and systematic effects within short and long term; the typical requirements for determining repeatability and within-lab reproducibility have been clearly outlined; more explanations on the main principles of modifying a model in a modelling approach have been given, together with an example. 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 pass six graded tests and get higher than 50% score from each of tehm. These tests are available to registered participants via the Moodle e-learning platform.

 

LCMS Method Validation online course offered by UTOn Feb 16, 2018 the on-line course (MOOC) LC-MS Method Validation finished successfully.

Altogether 424 (303 last year) people were registered from 71 (61 last year) countries. 236 (224 last year) participants actually started the course (i.e. tried at least one graded test at least once) and out of them 159 (168 last year) successfully completed the course. The overall completion rate was 37% (55% last year). The completion rate of participants who actually started the studies was 67% (75% last year). As can be seen, almost all these statistics are worse than they were the year ago. But then in the last year’s edition both completion rates were all time highest that our group has seen in any of our MOOCs. Thus we probably can be reasonably happy with the completion rates that we have now.

As has been the usual case with our online courses, 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 course 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 2018.

 

It was the spring of 2011 when I decided to apply to the AMS programme. If I remember correctly, the decision was based on my gut feeling and it was a right one. AMS was related to “perceived” world more than many other programmes in the faculty of science and technology as was also stated in the slogan “bridging the gap between measurements and society”.

5 years after the graduation I am still thankful for taking the journey, and I wanted to remind to myself and to others the three aspects that distinguished the programme from many others.

1) Combination of science and society. If you have the opportunity to combine your own favourite scientific topic (in my case biochemistry and measurement science) with knowledge about requirements related to law, regulations, and standards one has the possibility to give your thoughts a new perspective. It was beneficial for me in the labour market – there are not many people who know both of these aspects simultaneously which makes an AMS graduate a valuable specialist, mostly in private sector, but also in “pure” science. (I am currently working as a quality assurance specialist at Kevelt AS, which is a pharmaceutical manufacturing company in Estonia.)

2) Improvement of communication skills. There was a lot of group work during the studies, which improved my social skills. There is nothing more important than human relations! We had the possibility to study with people from Uzbekistan, Latvia, China, United Kingdom, Ukraine, Jordan, Romania, France, Turkey, and many more. This enabled to study about other cultures, but also how to communicate with people from other cultures.

3) The inspiring (!) lecturers. Their eyes were sparkling when they spoke about their topics so vividly. I believe that people are best at what they really love to do and I aim for the same in my professional career.

I could not thank Prof. Ivo Leito more for such an important contribution to our (students´) lives as leading the AMS programme. He is passionate about what he is teaching and sincerely interested in answering the endless questions, giving us the opportunity to find our better selves in the progress of studies.

 

It is a pleasure to announce that the admission period is again open for the Applied Measurement Science master’s programme!

It is a programme in a field where there is a serious shortage of competent people all over the world. The reason is that the importance of measurements, tests and chemical analyses is constantly increasing. It has recently been claimed, and rightly so, that we are living in a Golden Age of Measurement Science!

It is also the pleasure to let you know that this is the 10th full admission cycle of the AMS programme! Ten years is sufficiently long time to take a brief look back.

During the ten years altogether 55 people have successfully graduated from the AMS programme. Our graduates are enjoying a variety of interesting careers: setting up a contract analytical laboratory, redefining the way people interpret and measure pH, developing new ion sources for mass spectrometry, working as vice-director at National Measurement Institute, Managing IT Infrastructure projects, etc. A longer list of positions held by AMS alumni can be seen in the AMS Career Outlook page.

We have every reason to believe that the row of exciting achievements will continue and we wish you all the success in applying to the programme!

Admission will be open until Mar 15, 2018.

 

Measurements and computations 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 works (Chem. Sci. 2017, 8, 6964-6973.,    J. Phys. Org. Chem. 2013, 26, 162-170.,    J. Phys. Chem. A 2015, 119, 735–743.,    J. Phys. Chem. A 2016, 120, 3663–3669.) the behavior of a number of acids – ranging from weak to strong and superstrong acids (superacids) was examined in three solvents (water, acetonitrile, 1,2-dichloroethane) and in the gas phase. Acidities (pKa values) of a number of different acids including the well-known superacids trifluoromethanesulfonic (triflic) acid, bis-trifylimide (Tf2NH), etc as well as the carborane superacids (closo-carborane superacids), but also 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 depnding on the on the nature of the acidity centre and the molecular structure are analyzed. The acidity orders are different in water, MeCN, 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 together with references to specific publications are collected in the Table below.

Table of pKa valuesa of acids in different solvents.

 

 

 

 

 

 

Acid

H2O

MeCN

DCEb

GP

GP

 

pKa

pKa

pKa

pKa

GA

 

 

 

 

 

 

Fluoradene

11.1

23.90

12.5

238

324.9

Para-Toluenesulfonamide, 4-CH3-C6H4-SO2-NH2

10.21

26.87

15.6

245

334.0

9‑C6F5‑Octafluorofluorene

10.1

18.88

9.0c

220

300.6

Phenol

10.00

29.14

19.6

251

342.3

(C6F5)2CHCN

9.5

21.10

10.3

229

312.4

C6F5CH(CN)COOEt

5.89

17.75

7.5c

230

313.5

2,4-Dinitrophenol, 2,4-(NO2)2-C6H3OH

4.09

16.66

4.7

226

308.6

(CF3)3COH

5.40

20.55

9.2

238

324.0

Acetic acid, CH3COOH

4.76

23.51

15.5

250

341.1

(4-CF3-C6F4)2CHCN

4.4

16.13

6.0

221

302.1

4-NO2-C6H4-CH(CN)2

2.3

11.61

0.3

220

299.5

Saccharin

1.80

14.57

5.5

232

315.9

Picric acid, 2,4,6-Trinitrophenol

0.40

11.00

0.0

219

299.0

(4-NO2-C6H4-SO2)2NH

<-1

8.19

-3.9c

213

291.1

(CF3SO2)3C6H2OH

-2.0

4.48

-6.6c

208

284.2

(CF3SO2)2NH

<-2

0.3d

-11.9c

210

286.9f

(C2F5SO2)2NH

<-2

-0.10

-12.4c

208

283.7

Cyanoform, (CN)3CH

-5.1

5.1

-6.4c

216

294.8

Triflicid, trifluoromethanesulfonic acid, CF3SO2OH

-14.7g

0.70

-11.3c

215

292.7g

Hydrochloric acid, hydrogen chloride, HCl

-5.9g

10.30

0.2c

241

328.1g

Hydrobromic acid, hydrogen bromide, HBr

-8.8g

5.5

-4.4c

233

318.3g

Sulfuric acid, H2SO4

-9e

8.7d

-2.2c

221

301.2f

Pentacyanopropene

-9.02

-2.80

-15.3c

196

267.2

Hydroiodic acid, hydrogen iodide, HI

-9.5g

2.8

-7.3c

227

309.3g

CB11H12H, unsubstituted closo-Carborane superacid

-25h

-17h

-25f

195

266.5f

B12H12H2, unsubstituted closo-Dodecaborate superacid

-17h

-9h

-17f

196

267.5f

CB11F12H, perfluoro-closo-Carborane superacid

-47h

-39h

-47f

156

212.8f

B12F12H2, perfluoro-closo-Dodecaborate superacid

-45h

-37h

-45f

156

213.4f

 

 

 

 

 

 

a Values from http://dx.doi.org/10.1002/poc.2946 unless noted otherwise. There are numerous comments and details to these values. Please see the original articles for details and comments. GA values are given in kcal mol-1. pKa values in the gas phase are approximate and have been obtained from the GA values by dividing with 1.364 kcal mol-1. b Ion pair pKa values relative to picric acid in 1,2-dichloroethane. c Values from https://doi.org/10.1039/c7sc01424d. d Values from http://dx.doi.org/10.1021/jo101409p. e Value from E. V. Anslyn, D. A. Dougherty, Modern Physical Organic Chemistry, University Science Books, Sausalito, 2006. f Values from http://dx.doi.org/10.1021/jp506485x. DCE values have been recalculated from absolute to relative, in order to be comparable with the rest. g Values from http://dx.doi.org/10.1021/acs.jpca.6b02253. h Crude estimates from DCE data by considering that bulk water is by 53 kcal mol-1 more basic than bulk DCE and bulk acetonitrile is by 42 kcal mol-1 more basic than bulk DCE.

 

(This post was initially posted on Feb 2, 2013. On Jan 15, 2017 a number values in the table have been replaced by more reliable values from more recent publications. In addition, some compounds were added to the in order to give a fuller picture. The changes concern only the table. The image has not been changed and should be viewed as illustrative)

_END_

This is a Golden Age of Measurement ScienceThe American Chemical Society (the world’s largest scientific society by membership!) has published a document titled Top Ten Trends Driving Science, which summarizes in an intelligent and engaging way the main processes and trends in the contemporary society that drive the scientific research. The explanations are supported by numerous quotes from leading scientists.

Of specific interest for our study programme is the trend No 2: Big data is more essential than ever, is which supported by quote from Jonathan Sweedler, Editor-in-Chief of Analytical Chemistry, stating among other things: This is a Golden Age of Measurement Science!

All the best wishes to all measurement scientists – both chemical and physical – everywhere in the world!

 

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