Chromatography Forum

Hi I am currently calibrating a Waters 2996 PDA detector, but it is failing for the 522nm peak the tolerance set is +- 1.5nm I am getting the peak at 524.1nm. I have replaced the Lamp but I am still getting the same results with the new Lamp. Any body any ideas about what could be causing the problem.

Thanks

The only thing I can think of that would cause that is a misaligned diffraction grating but I've never actually seen that happen and can't give any guidance as to how to fix it. It is probably not a do-it-yourself issue, unless there is a software fix.

try to read the energy , if it low replace M1 and M2/3
If the problem is still exist, you must replace grating

The dirty flow cell window cause this phenomena. Wash or change the flow cell window.