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.
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.
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.
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.
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.
- What is AMS ?Introduction, what students say, ...
- Study programmeCourses, key competences, ...
- AdmissionWho should apply, dates, documents ...
- Tuition fees, scholarshipsRequirements, information, ...
- Career outlookCan I find job after graduation?
- Living in EstoniaEstonia,Tartu, jobs, ...
- BlogOur professors blogging
- ContactPhone numbers, addresses, ...