immobilized stationary phase

[vvreddy]

Is any one know what is immobilized stationary phase in HPLC chiral column.
what is difference between coated and immobilized stationary phase.
In Chiralpak AD packing composition is
amylose tris (3,5-dimethyl phenyl carbamate) coated on silica .
Where as in Chiralpak-IA it is
amylose tris (3,5-dimethyl phenyl carbamate) immobilized on silica.
what is the diffrence?

[tom jupille]

"Coated" is just what it sounds like; the layer of stationary phase is like a coat of paint on the support. It is not chemically attached and so is somewhat fragile.

The immobilized phase is chemically bound to the substrate.

[vvreddy]

Thank you very much sir.