Webinar “Mobile Phase pH in Liquid Chromatography”

On Apr 29, 2021 the webinar “Mobile Phase pH in Liquid Chromatography” took place. Altogether 101 people participated from 41 countries, ranging from Portugal to Philippines and from Peru to Nepal.

It is well known that in liquid chromatography, mobile phase pH is an important parameter, significantly affecting the retention of acidic and basic analytes. Yet, mobile phase pH is tricky to measure because mobile phases are usually aqueous-organic mixtures and in the case of gradient elution mobile phase composition gradually changes during elution. The topics covered during the webinar were:

— Different possibilities to express pH in liquid chromatography (LC)
— Unified pH (pHabs): the concept and measurements methods
— The applications and limitations of different pH expressions in LC

Numerous questions were asked by the participants that indicated the importance of the topic and the need for a more robust conceptual framework for handling the topic of pH in liquid chromatography. Contributing to this, via the pHabs concept, is one of the aims of the UnipHied project.

The webinar was organized in the framework of the PRG690 project from the Estonian Research Council and the  UnipHied project (www.uniphied.eu), which  is funded from the EU’s EMPIR programme, co-financed by the Participating States and from the European Union’s Horizon 2020 research and innovation programme. Additional support from: EU Regional Development Fund (TK141 “Advanced materials and high-technology devices for energy recuperation systems”) and Estonian Center of Analytical Chemistry (www.akki.ee)


 

 
 
 

Webinar “Mobile Phase pH in Liquid Chromatography” on April 29, 2021

It is well known that in liquid chromatography, mobile phase pH is an important parameter, significantly affecting the retention of acidic and basic analytes. Yet, mobile phase pH is tricky to measure because mobile phases are usually aqueous-organic mixtures and in the case of gradient elution mobile phase composition gradually changes during elution.

Mobile phase pH is the topic of an upcoming webinar “Mobile Phase pH in Liquid Chromatography”, which we will organise on 29.04.2021 at 13:00 – 16:00 (Central European time: France, Germany, …) via the Zoom platform. Registration to the webinar is now open at this registration link.

The topics that we plan to cover are:

— Different possibilities to express pH in liquid chromatography (LC)
— Unified pH (pHabs): the concept and measurements methods
— The applications and limitations of different pH expressions in LC

The webinar is organised in the framework of the project 17FUN09 “UnipHied”, which is funded from the EU’s EMPIR programme, co-financed by the Participating States and from the European Union’s Horizon 2020 research and innovation programme.

 

 

 

 

 

Our acid-base research at 19th European Symposium on Fluorine Chemistry 2019

On 26.08.19 at 19th European Symposium on Fluorine Chemistry 2019 Ivo Leito gave a talk Acidities of molecules and media: the united pKa-pHabs scale in 1,2-dichloroethane.

For the first time in a low-polarity solvent, the scale has a dual nature, being both a pKa scale of the involved acids (i.e. describing acidity of molecules) and at the same time a pH scale, describing the acidity of the solutions (media).

The scale spans 28 orders of magnitude (pH or pKa units) and is composed of 87 acids of diverse nature. The scale is linked to the unified acidity (pHabs) scale and expressed in values, which makes the acidities of the solutions directly comparable to the conventional aqueous pH scale. This in turn makes the scale a useful tool in future studies of acid-driven processes (reaction mechanisms, catalysis, strong oxidants, etc) in low-polarity media.

This work has been published in: Chem. Sci., 2017, 8, 6964-6973. A unified view to Brønsted acidity scales: do we need solvated protons?.

It is part of a larger endeavor – to promote a wider usage the unified pH scale by the research and technology communities, which is currently in progress via the UnipHied. The project 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.