Problems in Acarbose - Urgent

[shanmuga]

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Dear Friends,
I am analysing Acarbose. Column is Thermo Hypersil APS-2 column. Mobile Phase is Acetonitrile:Buffer (75:25). For a new column RT is about 16 mins. But while running a sequence, RT is shifted (decreased slowly). At the starting of the sequence RT is 16.6 mins. After that slowly RT is decreased and at the end of the sequence , i got 15.3 mins. why this difference? and where is the problem? Can anyone help me.
Buffer Prep: 0.6 g KH2PO4 and 0.35 g anhy. Na2HPO4 in 1000 ml of water.

And how to maintaining this APS-2 column? For washing this column is water only suitable. ? Please help me.

[Uwe Neue]

An aminopropyl bonded phase is not stable under these operating conditions. To get good and reproducible results, you need to use an amino phase that has been stabilized, such as the Carbohydrate Analysis Column from Waters.

[Bryan Evans]

We have a new aminopropyl phase that is durable under highly aqueous mobile phase conditions. Anyone using a USP L8 (aminopropyl phase) column that is experiencing poor column lifetime / reproducibiliy issues should try Unison UK-Amino:

http://www.imtakt.com/TecInfo/TI304E.pdf

[shanmuga]

Dear friends,
i want any other solutions by using the same column friends.