Omeprazole Assay

[haiyen]

I need some advice about assaying Omeprazole. The HPLC condition: C18 Waters, mobile phase Disodium hydrophosphate 0.05M: ACN (65:35) pH 6.5, UV detection 302 nm. I want to know how to clean the HPLC system after assaying (with which solvent, how long)
Look forward to your reply. Thank you so much

[tom jupille]

Generally speaking, flush the system out with the same mobile phase, but without the buffer (i.e., 65:35 H2O:ACN). Usually about 10 times the column volume will suffice (you didn't say what size column you are using), plus some additional for the rest of the instrument. 50 mL should be plenty. After that, flush the column with whatever Waters recommends for long-term storage (or just use 100% ACN).

[zokitano]

Try to read the maintenance instructions about cleaning and storing the column in the paperleaf that comes with your column.
If that kind of instructions aren't included, then flush the column (after the assays) with water:ACN = 90:10 (v/v) at flow rate 1,5 mL/min for about 30 minutes (to remove the salt from your previous mobile phase), and then subsequently increase the ACN content in your mobile phase for 20% at every 10 minutes. At the end store the column purging it with pure ACN (100%) for about 10 minutes.

Best wishes

[pharmason]

wash your column with same buffer:Acetonitrile ratio just replace buffer with Dionized water and was for about 20 minute for 250 cm long column and 10 minute for 150 cm long column, then wash with 100% Acetonitrlile and store the column.

[haiyen]

Thank you all for your help. I will post my result of assaying as soon as possible.
Besh wishes!!