Chromatography Forum

We are using a Perseptive Biosystems Fluor-304 fluorescence detector for analysis of derivatized amino acids. The unit is working fine, but emits a high-pitched noise when turned on. The sound disappears momentarily when the unit is autozeroed but then returns immediately. Is it normal for a fluorescence detector to emit such a sound? It does not appear to be altering its performance, just rather annoying.

Thanks for any info that anyone might have...

Folive

I'm not familiar with this specific instrument, but most fluorescence detector these days use a xenon flash lamp as the light source. What you hear is probably either the rapid discharge of the lamp or the high-frequency high-voltange power supply for the lamp.

I also suspect the lamp and/or the power supply. I also urge you to take action. It is my understanding that xenon flash lamps can fail explosively. If this were to happen, it could possibly trash the entire detector.

What is the condition of the lamp? Can you swap it out with a new one? If so, I would make the swap. If the sound remains after lamp replacement, then I would suspect the power supply.

There is one other possibility. These detectors have to have pretty big cooling fans. You fan may be producing a whine. In which, it needs replacement.

Many thanks for your important suggestions. I will check on the age of the lamp, power supply and fan and fix if necessary.

FOlive

Please, do not panik about the noise. I have lived through the high-pitched noise of Xenon flash lamps in the mid-80's. You could hear every data point...

I have four Agilent FLDs. They all whine at a frequency that is dependent on the flash lamp frequency, so the posts that refer to that are correct. The frequency of the flashes is in the several hundred Hz range and you are hearing harmonics relating to that. I would contact the mfgr to verify.

If I DON'T hear that whine when the detector is supposed to be "on", THEN I worry !

Thank goodness for my quiet Jasco detector. Just a pleasant hum from the cooling fan. I hate high-frequency noise.

In my case, I guess I should be grateful for having played bass guitar in my youth. I can't hear anything much above 10 kHz

The lack of high frequency noise is the best thing about LCD monitors. If you have an old noisy CRT, you should consider replacing it. There was an old CRT next to my desk for a while. People looked at me strangely when I would periodically lean over and whack it to shut it up. I think I was the only one who could hear it. I'm prone to leaving the building whenever anyone starts up a spraydryer too.