related substances of papaverine 2

[asouliot]

I have a question regarding the determination of related substances of papaverine.
According the European Pharmacopoeia the stationary phase must be base-activated octylsilyl silica gel (5μm). Since I have used this kind of stationary phase the relative retention time of noscapine (relative substance) is bigger than 1, and based in European Pharmacopoeia the relative retention time must be about 0,9.
Can someone suggest a me stationary phase in orded to solve this problem?


Thank you

Andreas Souliotis[/b]

[tom jupille]

There can be tremendous selectivity variations among columns which the various pharmacopieae class as "equivalent".

Go back to the monograph, look up the original citation and use the same brand of column.