Peak brodening in Chiral pak-AD column

[vvreddy]

In atorvastain calcium for chiral purity by HPLC we analyzed on Chiral pak-AD column (250*4.6,10u)-As per EP monograph. In the beginning peak shape is good. One week later when we started to analyze another sample the peak shape became broden too much.The mobile phase is Hexane, dehydrated alcohol and trifluoroacetic acid in the ratio of 940:60:1 (v/v/v).
we washed the column with Isopropyl alcohol at 0.3 mL /minute flow rate and also with Ethanol at 0.3 mL /minute flow rate.But problem is not resolved.

Is there any thing i can do other than this,plz help.

[achkata]

Hey,
did you solve the problem?
I had similar problem with another sample on Chiralpak IA, but after washing with DMF it was ok.
greetings

[vvreddy]

DMF is a forbidden solvent for Chiral pak-AD column.So it don't work.

[achkata]

hi,
I supposed that dmf is forbidden for AD colum, follow the instructions in column documentation, if this don't help contact Diacel. They'll give some recommendations.
usually column requires much more time to "wash" it, when additives have been used. did you try?


greetings