Qualitative understanding of partition preferences

Introduction
Cavity model
Rules for partitioning
The cavity model in quantitative terms

Selftest
     1) What does the cavity model say?
           Answer
     2) Main interactions ... ?
           Answer
     3) Size of a solute  molecule ... ?
           Answer
     4) Size of the solvent  molecule ... ?
           Answer
     5) Interpretation of data
           Answer
     6) "Like dissolves like"
           Answer
     7) Concept maps
     8) Functional groups
           Answer
     9) Illustration by given data?
           Answer
     10) Evaluation of the software PcKocWIN
     11) H-bonds between given substances?
     12) Tendency to distribute
           Answer
     13) Gas chromatography
           Answer
     14) Henry's Law constant
           Answer
     15) Quiz
Problems
Intermolecular interactions in every day life
FAQ

13) Gas chromatography

 

Question:

An environmental sample shall be analyzed for ethylbenzene and phenol by gas chromatography. One finds that it is impossible to achieve a satisfying separation on an Apolane87 stationary phase (Apolane87 is a branched alkane). How should a stationary phase differ from Apolane in order to give a better separation of the two compounds?

 

Answer:

The problem is due to the similar vdW interaction of both compounds and the fact that retention on a APOLAN phase is only caused by vdW interactions. Any stationary phase that is a H-bond acceptor with interact differently with both compounds and thus allow a separation.

 

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