I haven't done forced degradation before. Now I need to do a complete forced oxidation to tris(2,4-ditert-butylphenyl)phosphite (Irgafos 168). I was thinking to use hydrogen peroxide. Please advise, what would be good starting conditions (concentration of H2O2 to add, volume of added H2O2, reaction time, temperature)?

Can I inject directly to C18 column after degradation? Or do I need to remove/neutralize H2O2?

Many thanks in advance!

Try 0.3% H2O2 at 1 to 3 days at 5C and RT (both in dark). Inject 25ul should be fine. Also inject a blank peroxide solution also (also store in dark). Ideally, you should use AIBN (1:1 molar AIBN to drug) to mimic autoxidation. Stop when you have reach approx 10% degradation. You may have to increase the peroxide conc. (3%) or change the exposure time (either shorter or longer). Quenching may not be necessary, however, if you want to, try using molar equivalent of sodium thiosulfate.

>By Anonymous on Friday, June 27, 2003 - 07:36 am:

Hi, I was wondering if you have a reference for using a free radical initiator or quenching peroxide reactions for forced degradation studies.
Thanks.