[BiomolecularLee]

We've been having some trouble getting clean spectrum from our Thermo Nicholet iS10 FTIR.

When I take a look at the background, I can see the CO₂ doublet at 2400 cm^-1, but the baseline on either side of that is extremely noisy.  I know there will be some noise from water and other things, but the whole baseline is noisy.  After correction, the spectra it produces still contain tons of noise and are almost unreadable.

I ran the performance verification in the software, and the energy ratios are okay, but every single noise level test failed.  For example, it says peak to peak noise at 550-450 is 117.2 and the maximum is 3.0.  The wavenumber accuracy and intensity repeatability mostly passed, so the problem seems to be mostly with noise (probably too much noise for the peak-picking algorithms to work).

Also looking in the experiment setup window, I do not see any kind of interferogram showing up (just a flat line).  But when I click the box to show the reference then I see a small interferogram.  I also tried the alignment option in the setup but that didn't help at all.

The IR is about six years old, and it was last serviced two years ago.  The desiccant indicator is still blue, and it is hardly used (maybe only about 5 hours a year).

So can any IR gurus out there give us a clue what might be wrong?  Does it sound like the source is going bad?  Or is it something more severe like a KBr beamsplitter or a detector? Thanks.

[marquis]

Many problems can cause the excessive noise, but my first guess is the source.
The source is one of the first things to go bad.

Can you call Nicolet's tech service and have them help you with it?  Unless they've
changed, that used to be free.

Good luck.