Chromatography Forum

Hello to everyone,
this is my first question here! And it could be very easy, but it is making me so annoying...
I am trying to use an Agilent LC compact 1120 for the determination of phenols in waste and water, with eluent gradient ACN/H2O, but as I start checking the baseline the noise test gives me 4000 as agains the ideal value of 50! I have cleaned the cell with H20/H2SO4, checked every part of the instrument, and nothing changed. The software EZ Chrom Elite gives me the instrument status allright.
Another issue which makes me crazy is that everytime I open a new chromatogram or I run a new sample, this is automatically opened with other old chromatograms that I cannot either delete!
I will be very grateful to anyone will answer.

Thank you!

Hello to everyone,
I am trying to use an Agilent LC compact 1120 for the determination of phenols in waste and water, with eluent gradient ACN/H2O, but as I start checking the baseline the noise test gives me 4000 as agains the ideal value of 50! I have cleaned the cell with H20/H2SO4, checked every part of the instrument, and nothing changed.

First of all, check what the baseline looks like with the pump turned off. Is it still noisy? Then the problem is within the detector - maybe a new lamp is necessary? If the noise is much better with the pump off, than have a look at the pump - check-valves working properly, any leaks, pressure constant, mixer OK,...?

Another issue which makes me crazy is that everytime I open a new chromatogram or I run a new sample, this is automatically opened with other old chromatograms that I cannot either delete!

You mean overlaid chromatograms? Try to right-click on the chromatogram and select "clear overlays".

The instrument doesn't allow me to check the baseline with the pump off, it automatically turns it on.
For what it concerns the chromatograms, when I click on "clear overlays" nothing happens. Moreover, I deleted these chromatograms (it always opens the same three chr.) and now it opens just the window without any track.
I've started to use this instrument for few weeks...

Can't you turn the pump off in the "pump" dialog WHILE the baseline check is running? That's what I usually do - let the baseline check run with the pump on for a few minutes and then turn it off, so I can see directly the change in the baseline noise.

I have tried to use the Agilent Lab monitor and diagnostic software, even though I can only run some tests because it requires special kits that I cannot either find on the website. Who has used it and can tell me something more about?
I cannot turn the pump off during the run, it doesn't allow any change of the conditions during it.

Let the pump on , but do not connect it to the detector ( or column ).
Simply route the pump outlet to waste , and fill the detector cell with a syringe.