Eurachem 2019 workshop: Validation of targeted and non-targeted methods of analysis

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”!

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).

We are hoping to see many of you in Tartu in May!

 

The biggest development of the SI system in decades!

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)

 

UnipHied EMPIR Network at Baltic Electrochemistry Conference 2018

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 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.

 

UT analytical chemistry education activities at EcoBalt 2018 Conference

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

The presentation contains information about the online 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 the 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”.

 

Is it possible to use data below the limit of quantitation in pharmacokinetic studies?

Results below the limit of quantification (BLQ) are generally not reported or reported without explicit numbers, leaving pharmacokinetic (PK) and pharmacodynamic (PD) studies wishing for more information to improve their model parameters. But the laboratory cannot release actual values BLQ since the quality of that data has never been assessed.

Possible solutions to this unfortunate situation were investigated in a recent perspective article led by our group and published in Bioanalysis. The article titled: “Utilization of data below the analytical limit of quantitation in pharmacokinetic analysis and modelling: promoting interdisciplinary debate”, expanse the so far used statistical salvage of information, by an experimental addition to investigate the quality of data BLQ.

By directing this article towards the pharmacometrician, the analytical scientist and the regulatory personnel, we hope to encourage an inter-disciplinary discussion to improve the situation by finding ways to use BLQ data in PK/PD studies, in order to enhance the quality of the obtained pharmacokinetic models. Several ways were proposed for moving forward, in particular improving/modifying method validation guidelines for enabling to use BLQ data and leaving the decision regarding whether and how to incorporate the BLQ data into a PK/PD model to the data analyst and not the analytical chemist.

Comparative validation of amperometric and optical dissolved oxygen sensors

A comprehensive comparative validation for two different types of dissolved oxygen (DO) analyzers, amperometric and optical, together with estimation of measurement uncertainty is presented in the recently published article I. Helm, G. Karina, L. Jalukse, T. Pagano, I. Leito, Environmental Monitoring and Assessment 2018, 190, 313.

A number of performance characteristics were evaluated including drift, intermediate precision, accuracy of temperature compensation, accuracy of reading (under different measurement conditions), linearity, flow dependence of the reading, repeatability (reading stability), and matrix effects of dissolved salts. The matrix effects on readings in real samples were evaluated by analyzing the dependence of the reading on salt concentration (at saturation concentration of DO). The analyzers were also assessed in DO measurements of a number of natural waters. The uncertainty contributions of the main influencing parameters were estimated under different experimental conditions. It was found that the uncertainties of results for both analyzers are quite similar but the contributions of the uncertainty sources are different.

The results imply that the optical analyzer might not be as robust as is commonly assumed, however, it has better reading stability, lower stirring speed dependence, and typically requires less maintenance. On the other hand, the amperometric analyzer has a faster response and wider linear range.

(Photo by Lauri Jalukse: measurements of dissolved oxygen concentration with amperometric and optical analyzers at Jordan spring, Karksi-Nuia, Estonia)

 

Dissolved Oxygen Measurement Training in Uruguay

Irja_Helm_Conducting_Dissolved_Oxygen_Measurement_Training_in_UruguayDuring Jun 12-16, 2017 research fellow Irja Helm from University of Tartu, Institute of Chemistry is conducting a training session on high-accuracy dissolved oxygen measurement in Montevideo (Uruguay). The local organiser of the training is LATU (Laboratorio Tecnológico del Uruguay). There are 8 participants in the training, from Uruguay, Argentina, Ecuador and Peru.

The training is centered around the high-accuracy Winkler titration method of dissolved oxygen concentration measurement that Irja developed during her PhD study: I. Helm, L. Jalukse, I. Leito “A highly accurate method for determination of dissolved oxygen: Gravimetric Winkler method” Analytica Chimica Acta 2012, 741, 21–31. The training is interesting in the sense that most of it is carried out in laboratory, where participants do measurements hands-on. The experimental setup was assembled jointly by LATU and by Irja. The practical orientation is well in line with the main purpose of the training – to introduce the high-accuracy Winkler method to the reference laboratories in the participant countries.

The training is organised in the framework of the project „Regional Quality Infrastructure Fund for Biodiversity and Climate Protection in Latin America and the Caribbean“ (VH-No.: 95094) coordinated by PTB (Germany).

(Photo: Irja Helm, on the left, together with training participants in laboratory)

 

Metrology in chemistry in a nutshell

Random_and_Systematic_Effects_TimelineIn a recent edition of the premier journal devoted to quality and metrology in chemistry Accreditation and Quality Assurance Ivo Leito has attempted to express in very simple terms the essence of Metrology in Chemistry. In the article Accred. Qual. Assur. 2015, 20, 229–231 he arrived at three main recommendations:

1. Whenever possible, comparisons with reference values should be carried out. The reference values can be realized in different ways: Certified reference materials (CRMs), Laboratory reference materials (LRMs), Measurements with reference methods, etc.

2. Data on stable samples should be collected over long time periods (e.g. as the X chart), in order to evaluate as many sources of variability in the analysis method, as possible. The longer the time period, the more systematic effects will become random and thus easier to evaluate (more on this topic can be found in a recent review on bias).

3. “Do not stop there!”, meaning that the above mentioned activities should run in a lab on a continuous basis.

As a conclusion, it can be said that constant improvement is the key to reliable analytical results.