agilent 1100 baseline issue

[Chomps]

Hi everyone.

I am experiencing a sine type wave on my agilent hplc. Its an 1100 series 1315A DAD detector. I have done searches and checked the archives and have already tried all the tips that I have found.


this picture is of just the detector noise. the flow cell has been removed. there is nothing else turned on and the detector is the only thing plugged into a UPS which is not plugged into the wall.

This has been plaguing me for awhile and have seen it through different detectors, lamps, rooms. the only thing it could be that I can think of is some other sort of environmental interference.

Any other thoughts would be greatly appreciated,
Thank You
Amanda

[Consumer Products Guy]

Have you tried changing the UV lamp?

I had 1100 DAD baseline issues in 2013, intermittent, not related to pump, flow cell, etc. New lamp cured that.

[bunnahabhain]

I had a similar sine shaped baseline (delta t about 2 s) and successfully cured it by changing the piston seals:
http://www.chem.agilent.com/cag/cabu/lcvideoindex.asp
(you will have to create an agilent account, but it's worth it)

Good luck
Jörg

[Chomps]

I have been seeing this on and off for over a year now. Its seen three different lamps, 2 different detectors(same models) and moved it to different rooms. The pump isn't on in the picture and the flow cell is not in. It is, not 100% of the time however there seems to be no correlation of time when it happens and doesn't happen.

[uzman]

Did you try to connect the unit directly to wall socket , without using UPS ?

Some UPSs produce noisy output voltages , not ideal sinewave , and this may cause such problems.

Also check the earth ( ground ) connection of the wall socket , if it is connected and has ideal voltage levels ( max 0.6-0.7 volts between neutral and ground)

[Chomps]

I've only had it plugged into the UPS for the last two weeks and still saw the same problem before.

I will have to check the ground but i have had it in different outlets, so maybe the whole building is bad.

I actually to the detector home last night to try it in a different environment to see if it would make a difference and it did. I saw no wave over a period of several hours. So it must have something to do with the location.
Thanks Guys
Amanda

[daniel_aut]

Try an UPS on the detector and PC.Shutdown any other "electricity hungry" equipment in the immediate vicinity.

[LCbob]

Hi

Its probably caused by the ambient temperature changes in the lab. Agilent changed the design ( G1315B ) to put a heater in the optics bench to remove this issue.

[t_morris]

I think it is an improper ground like uzman said. I ran into similar issue on both agilent detectors for six 1100s. Please let us know what was the interference.

[Chomps]

UPDATE,

Still have not figured out the problem. found a room in the lab that the instrument worked in. As long as the door was shut, there were no baseline issues. however it is not able to stay in the room because we are getting another analysis online and will need the space.
I ran it for one day and had zero issues, which im hoping ruled out a grounding issue, but the three MS's in the room were not running. the next two days, some of them were running and the baseline noise was back. Now I'm just gonna have to wait for a day when they are off.
Thanks for everyones input.

[t_morris]

Okay...well then it sounds like it is solved. You are pulling too much electricity from that line. MAybe see if you can get an electrician to divide up the lab outlets on separate lines? It may be a little costly, but that should do the trick.

I had same issues and I presumed the UPS would insulate the system from this issue.

Thanks for the update on your problem

Tim