Chromatography Forum

i suspect that my photodiode array detector got problem. Any standard way to check its sensitivity ? or just check whether it is working fine or not

More details would be helpful (what is the brand and model number of the detector, what seems to be the trouble, what are the results of internal diagnostics and calibration checks?...).

it is a Waters photodiode array detecor (2998? maybe).
Now I got some problem of reproducibility.
cannot reproduce the results obtained weeks ago.
the previous peaks disappear and now only one solvent peak.


Now 3 things to check.
the sample, the column and the detector.so i would like to start with the UV first

That system should do a power-on self-test, including a wavelength accuracy check. Did it pass that OK?

where i can find the self test? there is no button on it. and the control software is very simple. no way to check it through software-
it shows no problem when switch on.
just want to know any method to check whether it is working fine.

Your best bet would be to get a service manual from Waters.

A good overall check is to prepare a solution of anthracene in water (about 2 micrograms/mL) and set up a reversed-phase column with Methanol/water mobile phase (about 80% MeOH, but you may have to tweak that to give a k' of about 5 for the anthracene peak). Inject 10 microliters of the anthracene solution and get a spectrum as it elutes. The absorbance maximum should be at 251 nm.

Hi,

How do you access the PDA detector? Through a console or through the diagnostic. 2996 is accessed through the diagnostic as the 2998 has a console like an Acquity.
As Tom pointed out, when the PDA detector is powered On it goes through a full Diagnostic test. Both Lamps on the front of the PDA change from blinking to Solid when it has passed.
The serial number can tell what type of detector it is also if your not sure.