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How can we separate E and Z isomer on C18 column (non-stereospecific)?
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+ Stereochemistry
+ Isomerism
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Kevin Landgrebe
How can we separate E and Z isomer on C18 column (non-stereospecific)?
Let's assume for a moment that you are talking about alkenes... In principle, the E and Z isomers should have different properties (dipol moment, van der Waals properties, etc) which should be reflected by different retention times on a C-18 column. However, the question is: how big the differences are... Column length and mobile phase will be two important parameters here. In particular, acidic modifiers of the mobile phase (like AcOH or TFA, make sure there is no E/Z isomerization occurring on the column) can be helpful. Some transition metal salts can also be used but, again, one needs to be able to exclude the E/Z isomerization. Thus, it all depends on the particular case.
Let's assume for a moment that you are talking about alkenes... In principle, the E and Z isomers should have different properties (dipol moment, van der Waals properties, etc) which should be reflected by different retention times on a C-18 column. However, the question is: how big the differences are... Column length and mobile phase will be two important parameters here. In particular, acidic modifiers of the mobile phase (like AcOH or TFA, make sure there is no E/Z isomerization occurring on the column) can be helpful. Some transition metal salts can also be used but, again, one needs to be able to exclude the E/Z isomerization. Thus, it all depends on the particular case.
It depends on the functional groups present in your compound and changes in their orientation in E/Z configurations. Copper has been used to form complexes with the analyte. Due to the changes in orientation, only one (E or Z) forms complex with the metal drastically changing the retention characteristics lead to separation of E/Z isomers.
It depends on the functional groups present in your compound and changes in their orientation in E/Z configurations. Copper has been used to form complexes with the analyte. Due to the changes in orientation, only one (E or Z) forms complex with the metal drastically changing the retention characteristics lead to separation of E/Z isomers.
Let's assume for a moment that you are talking about alkenes... In principle, the E and Z isomers should have different properties (dipol moment, van der Waals properties, etc) which should be reflected by different retention times on a C-18 column. However, the question is: how big the differences are... Column length and mobile phase will be two important parameters here. In particular, acidic modifiers of the mobile phase (like AcOH or TFA, make sure there is no E/Z isomerization occurring on the column) can be helpful. Some transition metal salts can also be used but, again, one needs to be able to exclude the E/Z isomerization. Thus, it all depends on the particular case.
Let's assume for a moment that you are talking about alkenes... In principle, the E and Z isomers should have different properties (dipol moment, van der Waals properties, etc) which should be reflected by different retention times on a C-18 column. However, the question is: how big the differences are... Column length and mobile phase will be two important parameters here. In particular, acidic modifiers of the mobile phase (like AcOH or TFA, make sure there is no E/Z isomerization occurring on the column) can be helpful. Some transition metal salts can also be used but, again, one needs to be able to exclude the E/Z isomerization. Thus, it all depends on the particular case.
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It depends on the functional groups present in your compound and changes in their orientation in E/Z configurations. Copper has been used to form complexes with the analyte. Due to the changes in orientation, only one (E or Z) forms complex with the metal drastically changing the retention characteristics lead to separation of E/Z isomers.
It depends on the functional groups present in your compound and changes in their orientation in E/Z configurations. Copper has been used to form complexes with the analyte. Due to the changes in orientation, only one (E or Z) forms complex with the metal drastically changing the retention characteristics lead to separation of E/Z isomers.
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