Possibly a very simple question

[sianq]

....what causes electrical spikes in chromatography?

I've only ever explained them away as 'electrical spikes, don't worry about it'.

Now QA are asking questions about the cause!!

[Syntaxerror]

Please, may we have more information ? What kind of detector, mobile phase, system....

[DR]

Old UV lamps can cause this - another symptom of a UV lamp being past its prime is reduced response at lower wavelengths.

[key4]

I face that problem twice,
the first time the problem was a RF interference (it was a comunication antenna on the other side of the wall) and only occur in instruments with analog conections, (that means std cables not IEEE or TCPIP)
the second time I so it was becaose the uv lamp was with low energy and some sensor in the instrument tested the lamp as off and it tries to swich on (with a voltage pulse) every 10 to 15 minutes and that apears in the chromatogram.
If you are using instruments with analog conections take into account that cell phones can disturb too.

K4

[Mark Tracy]

Another source is sharing a circuit with some heavy electrical equipment like an air compressor. When the machine starts up, it can cause a momentary voltage drop.

Another source is the dreaded ground loop. This happens often when different modules of a system are plugged into different mains circuits. It can also be caused by connecting the shield of an analog cable at both ends.

Another source in electrostatic discharge.

[DR]

Yet another possible source: NMRs

[sianq]

Our production building is still under construction and there is no UPS at the moment so my guess was a power surge from the construction site.

The instrument is less than a year old with little use so a worn out detector is unlikely (but still possible).

Thanks for the help!

[DR]

D2 lamps do not age well, even if they are seldom used. Perhaps the lamp sat around for a while before it was put into the detector, that sat around for a while before it was shipped to you...

Answers to the questions above will assist those who would help you (what wave length, what type of detector, what brand & model...)

[rnelson]

I had a similar problem with a particular LC, we only saw it once every few months and we never could find the problem. We finally decided to retire the instrument.

Within a month or two after retiring this LC, we started seeing the same thing on a recently acquired instrument. Because of the similarity to our other problem, we looked at both systems and found the common denominator...the a/d converter.

Since we retired the first instrument, we kept the a/d converter not realizing it was the problem and installed it on this new instrument. Since replacing the converter, we have seen no further problems.