RP HPLC

[pansuriyagopal]

In reverse phase HPLC method, which mobile phase should be tried first?
Is there any criteria which guide us for mobile phase selection?

[Klaus I.]

In reverse phase HPLC method, which mobile phase should be tried first?
Is there any criteria which guide us for mobile phase selection?

Can you tell us more about your substance of interest, please? Also more information about your equipment, e.g. you HPLC and the availible columns would be helpful.

[skunked_once]

Is there any criteria which guide us for mobile phase selection?

The criteria for mobile phase selection depends on the type of sample, column, and detector. As Klaus stated, more information on your application is necessary.

In reverse phase HPLC method, which mobile phase should be tried first?

Whichever mobile phase fits the requirements of your sample and is compatible with your column and detector. There is no simple answer although methanol/water and acetonitrile/water are probably the most common mobile phases for RP HPLC.

[pansuriyagopal]

In reverse phase HPLC method, which mobile phase should be tried first?
Is there any criteria which guide us for mobile phase selection?

Can you tell us more about your substance of interest, please? Also more information about your equipment, e.g. you HPLC and the availible columns would be helpful.

i am working on combination dosage form. Pka values are 4.6 and 9.6
i am using HPLC instrument made by perkin elmer with UV detector. and column is C18.

[Klaus I.]

In reverse phase HPLC method, which mobile phase should be tried first?
Is there any criteria which guide us for mobile phase selection?

Can you tell us more about your substance of interest, please? Also more information about your equipment, e.g. you HPLC and the availible columns would be helpful.

i am working on combination dosage form. Pka values are 4.6 and 9.6
i am using HPLC instrument made by perkin elmer with UV detector. and column is C18.

Based on your details:
2 API to separate with RP-HPLC with a somehow C18 column
One API is a weak acid, the other a weak base
You have a somehow HPLC with UV-detector

My recommendations for you mobile phase:
Try 0.1 % TFA in water as mobile phase A
and 0.1 % TFA in acetonitrile (or methanol) as mobile phase B
run a generic gradient from 5%B to 95%B
The TFA (trifluoracetic acid should be at least LC-Quality, preferably taken from 1 mL ampullae)

I'm glad I could help you.

[pansuriyagopal]

Thanks for your suggestion!
I got good separation with use of triethylamine in small amount.