Error message--please help on Agilent 1100 with Empower

[moonchips]

Greetings,
I got this error message and got instrument failure. Did any one see this before? And why did this happen?
G1365B: Data invalid. At least for some diodes of the array, the data produced are invalid due to too much light at a diode or a gain setting.

When I got this error message, it happened that I changed my mobile phase from 0.05% perchloric acid/ACN to 0.1% formic acid/ACN. Is this just coincidence or formic acid does give me problem?

My chromatograms showed that I had elevated baseline for 0.1% formic acid/ACN comparing with 0.05% perchloric acid/ACN.

Condition:
Agilent 1100 drived by Empower
I injected 50:50 ACN/H2O 80 mcl.

Thanks a lot!

[mbicking]

Did you re-balance (i.e., "zero") the detector after changing mobile phases? The absorbance characteristics of the two mobile phases are completely different.

Check the diagnostics on the detector - spectral intensity, dark current, etc.

[moonchips]

I did some more investigation on this problem.

When I change to H2O/ACN mobile phase, that problem was gone. I did not re-balance anything between each mobile phase change.

The problem did not result in long time instrument failure. I can still run samples after restart everything.

The problem happens only with formic acid 0.1%/ACN at 1.3 min, which is about the void volume.

I think people are using formic acid quite often.

Do I need to set the peak width to be smaller (I had 0.1 min, 0.05 min)
Should I turn on the reference? (it was off when I had the problem)

best

[attila01]

You can solve this by changing the parameters "Margin for negative absorbance" to a higher value.
You may observed high negative absorbance at the beginning of the run.
An other crazy Empower message...
Attila

[DR]

^ that, or it's just a reference issue - you need to gather your reference spectra from another part of the chromatogram (a quieter part).