By A.J. on Wednesday, November 27, 2002 - 02:43 am:
I was wandering if it is possible to analize salicylic acid and betamethasone dipropionate (CAS-5593-20-4) simultaneously.
Methods for salicylic acid, that I found, employ C-18 or C-8 columns with mobile phases – 0,05M KH2PO4(pH 2,5 or3,0):MeOH (sometimes acetonitrile) or water:methanol:acetic acid (60:40:1).
Betamethasone diprop. can be analized with C-18; acetonitrile:water 50:50.
My question is: how will betamethasone dipropionate behave in low pH mobile phase?
I would appreciate any comments on this while I am waiting for standards to arrive.