Chromatography Forum

Hi folks,

I need to etermine if the drift and noise on my RI detector is too great and if I should get a new one or try to fix this one. This is a 1047 A detector on an 1100 HPLC from Agilent. I have the specs for the detector in RIU's but not in mAU's.. is there a way to convert these??

Any help would be much appreciated..

Thanks
- Hubert

I'd turn it on a day in advance and pump mobile phase through during that time to get its lowest baseline. You may find the 1047 is out of support.

Thanks for the response.

The machine is on all the time, and it looks stable from the baseline..

The problem that I do have is that from run to run the areas of the peaks that come off vary by large amounts. There are no leaks, pressure is stable, flows are good, brand new column and guard column (did the same thing with the old ones as well), temps are good.. so that lead me to believe that the issue is with the RI detector. It is fairly old, and I'm not sure how long these things survive for (not a very PM friendly piece of equipment). This equipment is ran everyday, 7 days a week, running around 30 analysis / day.

Anyways, so I ran the drift / noise analysis as suggested in the 1100 manual and now I have some results with the units being mAU, which is great, but the only specs I can find for the deterctor are in the RIU units.. so what I need to do is compare the 2.. do they make sense, are they within spec or is it time for a new detector??

Thanks for all your help..

- Hubert

I think most data systems are set up to expect 1V/AU. That means that your mAU s are are probably millivolts.

You need to dig into the RI detector specifications to find out how many volts/RI unit.