[lakers21]

Hello everyone,

I'm currently an intern in a company. I am establishing the protocol to acquire transmission spectra with an infrared microscope : it's the Nicolet iN10 MX. The sample is a grease. The laboratory where I work also provides a infrared spectrometer from the same manufacturer : Nicolet iS10.

I have one question : when I select the iS10 experiment setup with the iN10, the spectrum shows some "noise" (?) between 4000&3500, near 2350 and 500 cm-1. Do you know where it can come from? Is it because of the nearby atmosphere?

For the iS10, the sample is compressed between two KBr plates, and it is put inside the apparatus whereas for the iN10, the sample is in free air on a motorized platform, also on a KBr plate. I'd like to acquire "cleaner" spectra. Thanks a lot if you can help me and sorry for my mistakes (i'm French)

I added the iS10 spectrum, the iN10 spectrum with the same experiment setup and the iN10 spectrum with a higher spectral resolution (4), and one iN10 spectrum with a lower spectral resolution (16) which is cleaner.

http://hpics.li/079028a
http://hpics.li/af7be7e
http://hpics.li/fcaf699
http://hpics.li/f93d953

[Arkcon]

Your images are too large for me to view, my internet pipe is too small, but others may be able to compare them better, so stay tuned.

Anyway, yes, you can sometimes get noise in an IR spec, caused by CO2 in the atmosphere, or adsorbed onto the plates.  The IR spec experts at work would occasionally flush the chamber, or the KBr plates, with dry nitrogen from a clean tank, to get a better scan.  You can certainly try it, and see if it improves the scan.

Of course, one instrument or another could be slight out of calibration, or have slightly older optics or electronics.

[lakers21]

 Hi, thanks a lot for your answer.

The instrument was calibrated 3 weeks ago. I use KBr plates and I always clean them with petroleum ether. What do you mean by "adsorbed onto the plates"? The background is taken on the KBr plate without sample.