Additives in chiral separations

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Bhau
Bhau's picture
Additives in chiral separations

Hi,
    In chiral separations,
What is an additive ?  
Why do we use additives ?
What are their importance ?
What is the limit for the adding additives ?

Dr. Analytical
Dr. Analytical's picture
We use additives in chiral

We use additives in chiral separations to interact with the chiral molecules that we are trying to separate.  Two normal enantiomers will have identical chromatographic properties, and so will elute at the same time.  If we add a chiral additive to the mobile phase, it can combine with the enantiomers in different ways so that the resulting combinations have different chromatographic properties, and we can separate the two compounds.

The amount of additive can affect the separation, so we may change the concentration to improve the separation.