Chromatography Forum

Hello,

the European Directorate for the Quality of Medicines & HealthCare (EDQM) describes in the guideline PA/PH/OMCL (11) 04 (Qualification of Equipment) the periodic OQ/PQ of HPLC instruments.

For the part "pump", the testing of the proportioning ripple is described as follows:

The ripple of the gradient composition is the percentage of noise of the 50% line from the gradient program.

%R = 100*N/h50

%R ............ ripple
h50 ............. height of the 50% line
N ............... height of the noise line, measured during 1 minute in the linear region.

Limits: ≤ 0.2 %

The test is performed together with the gradient composition test, where the step with the 50%A/50% B composition is kept for 10 minutes.

What is the sense of this test an how is the limit justified?

Thank you very much for your help.

Regards

Florian

I'd say the sense of this test is to control the ripple (aka noise) introduced by incomplete eluent mixing and/or pump pulsations.
As for the limit...

Hello HPLCaddict,

thanks for your reply.

I think, you are right with your assumption that it might be the "noise" test.

As the units of the Y-axis are not 100% comparable between all instruments, I assume that the limit is outlined in relation to the 50% gradient level. Might this be correct?

Regards

Florian