Different methods same peak area ?

Hello,

We would likely need more information on the issue. I assume you are talking about area RSD between injections of the same concentration. Is this the only peak in the injection? If not is this the only peak with the issue? Have you done any other methods on the hardware that test injection repeatability for other compounds. 

Marty 

Hello

We are using agilent infinity ii 1260

During the developpement of the drug everything was fine we got the recommended percentage on the USP since we are using the method mentioned on the usp for assay.

But After 3 months while studying stability we got different values.

We tried everything new filters new column.

Lately we tried the method for assay of paracetamol-tramadol we excluded the wavelength of detection of tramadol we just wanted to test it.

The concentration of paracetamol is the same in standard and samples we got the same peak area with both methods.

I was just wondering was this just a coincidence. I want to know more about it if there is any ressources.

Hello,

I am going to move the post to the LC forum.

Marty

Hello

Ok thanks for help

Do you have a good run vs a bad run?  is the pressure the same?  stable?