Hello everyone,

I'm performing the characterization of chitin and chitosan samples from a company using FT-IR and its accessories. I am using the Thermo Scientific Nicolet iS50 FT-IR Spectrophotometer with the Smart Diffuse Reflectance (SDR) Accessory , but I am not able to obtain a correct spectrum for these samples. I'm using a double cup holder, where I am placing the KBr in the first hole to collect the background and in the second one a bit of my sample (for example chitin) and I mix it with KBr. Then, when I collect the background the spectrum is as I expected to be, but as soon as I push the sample holder until the end of the accessory and collect the sample I get small absorbance values and a very plain profile spectrum.

I would really appreciate some help understanding what I'm not doing correctly in order to improve it and obtain useful results.