While doing my experiment of transition metal complexes, in DMF Solution different spectra at different concentration with noise results shown, it does not show the particular peak at particular wavelength. I also did an experiment with an empty cuvette, that also had some noise.
If you have too much noise probably your lamp is about to be dead or your have an electronics problem.
There can be many reasons for noise appearance. But since noise is also present even when you use empty cuvette, this sounds like a technical problem with the instrument. As I am using Shimadzu UV-3600, which is similar to Perkin Elmer Lambda 35, (double beam instrument) only with wider optical range, and have seen similar problems with my instrument, I can hopefully point out some possible reasons for observed noise:
- first possibility is, as Teodoro Kaufman pointed out, a possible problem with the lamps which are maybe at the end of the lifecycle. What you can do here is try to increase the beam slit to let more light onto your sample to stabilize the spectrum, which will unfortunately reduces your spectrum resolution somewhat.
- second possible problem is misalignment of your lamps with the optical path (you can read about it in the manual) which reduces available light intensity which falls onto your sample.
- third problem might be the dirty reference sample, or improper baseline collection procedure.
- and the fourth possibility is the instrument calibration problem (most common on Shimadzu UV-3600) which happens due the improper use of the instrument when users try to make so called "0% correction" without actually knowing what it is (freaks me out every time when they do that! :-) ). Now, "0% correction" refers to the darkest possible point of detection of the instrument in contrast to the whitest possible point of the baseline reference. It has to be done with sample beam totally blocked off for any kind of light passing through. If not performed this way it introduces a lot of noise in the recorded spectra. As I am not familiar with Lambda 35’s calibration options you would have to check that out on your own, or maybe someone with more experience with that instrument can help you out.
I hope this helps out somewhat...
I have used an older version and when the A is greater than 4 it will look like noise, I would try the machine at circa 500 nm with nothing in either cuvette holder. You should see no absorption, if you get random noise then you have a machine fault (check the lamps are working first).
Is there anybody who knows while we work with a unit tyrosine solution and repeat reading the absorption of a Tyrosine solution in water and buffer 3 times, the absorptions are not the same ?
Perhaps your lamp is bad, the electronics has some problems or your simple is of an inadequate concentration.
Electronic components may create noise in your experiment that indicate your instrument is less sensitive now.
I have the same problem. Please tel me if you could solve your problem with noise in UV-Vis spectra.
Thanks a lot.
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