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electrolyte concentration range
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Youn

Joined: 29 Dec 2014
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Link to postPosted: Mon May 23, 2016 10:07 pmPost subject: electrolyte concentration range Reply with quote

Hello,

 

Thank you for reading this one first.

In the program, range for electrolyte conc. for log D is 0.1-0.25M. Why is it limited to this range? Reference mentioned the range as 0.01-0.25M in Csizmadia's paper.

 

Thanks! 

Daniel
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Joined: 22 Jan 2012
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Link to postPosted: Thu May 26, 2016 4:00 pmPost subject: Reply with quote

Hi, 

The lower concentration limit is actually 0.0, and the developers of the logD model had to choose 0.25 as an upper limit for the ionic strength, because that was the value they had corrections for. Back then our model was the first that took such corrections into account. 

What limits would you need for your calculations?

Thanks, 

Daniel

Youn

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Link to postPosted: Mon May 30, 2016 6:15 amPost subject: Reply with quote

Thank you for your reply.

 

Actually, i want low concentration. I need a reference to support the concentration of my solution that is because manual recommended me to select conc of electrolyte within 0.1-0.25 M and 'reference paper' of the manual ranged 0.01-0.25 M. I don't know why they have different range. Also, according to my runs, lower concentration had some error than higher conc. of electrolyte..

 

If you have any other reason or reference of it (0.1-0.25 or 0.01-0.25), please let me know. Thanks again! 

Daniel
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Link to postPosted: Mon Jun 06, 2016 10:30 amPost subject: Reply with quote

Hi, 

I can't send you any specific reference, but here are some useful info you can use for further research:

LogD is usually measured in series of standard buffer solutions of given pH with specific ionic strength, which is usually between 0.1-0.25. That is why we selected those concentration ranges. Lower concentrations are usually selected to minimize the interaction between organic molecules and inorganic ions that can alter the logD value.

I suggest you should look up some reference material on the measuring of logD in practice.

 

Daniel

Youn

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Link to postPosted: Tue Jun 07, 2016 7:33 pmPost subject: Reply with quote

Thank you Daniel. 

 

The reference i mentioned above is the one referred in the manual of chemaxon logP and log D plugin. I want to use 0.05 M, and reference and program represent the different range of electrolyte so i was confused.

 

Thanks again for the replies and i will do research more.

 

Daniel
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Link to postPosted: Wed Jun 08, 2016 9:39 amPost subject: Reply with quote

Hi, 

You can set the ionic strength in the logP/D plugin to 0.05 ! As a reference please make some research in the practical literature.

And if you find bad results @ lower concentrations, send us a bug report with molecules and data attached. 

Daniel

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