Analysis of Isomers of analyte!
Posted: Wed Mar 16, 2005 10:52 pm
by adams
how is the analysis of isomers of analyte being carried out by HPLC
how is the separation of cis and trans isomer achieved.
under what stress conditions a cis isomer can interchange to trans and vice-versa.
any suggestions ?
regards
adam
Posted: Thu Mar 17, 2005 7:41 am
by HW Mueller
It´s the same as for any other compounds, you hope for a difference in the ratio of adsorbed (or other interaction with the stationary phase) to dissolved (mobile phase) molecules.
The separation of cis from trans is often quite easy as the isomers usually have totaly different geometry, thus different van der Waals etc. interactions. Look at the difference in melting points, or boiling points, depending... (these are, of course, also depending on intermolecular interactions).
A double bond which is isolated from other functional groups (has only H or several CH, CH2, CH3 groups attached to it) is quite stable, strong acids, some metal ions, high temps may cause equilibration between cis and trans. Check any organic text.