The purpose of this experiment is to use IR spectroscopy to identify four different over-the-counter pain medicines. You will be given a sample of one of the four pain medicines ( aspirin, acetaminophen, ibuprofen, or naproxen. You will then prepare the sample for scanning by the FTIR and then identify it from the resulting spectra.Your lab book introduction should therefore, include:
- the theory behind infrared absorption spectroscopy, especially as it relates to FTIR.
- information about the operation of an infrared absorption spectrometer, with diagrams of its internal schematics, and a short description of how each of the following parts works:
- light source
- interferometer
- detector
- recorder/analyzer
- briefly compare Nujol mulls, KBr pellets and "neat" samples.
Prepare a Nujol mull for your sample. Use only a small amount of the sample and a couple of drops of the Nujol. Grind together thoroughly and then put a small amount of the mixture onto a salt plate that has been cleaned with acetone. Assemble the holder with the salt plate and run a scan on the FTIR. Use the Omnic library and determine the identity of the sample.Results and Discussion:
Summarize the types of bonds present in your sample. Draw the structural formula and relate the different groups in the molecule to the different peaks seen.Obtain a copy of the spectra for the other three samples and do the same thing.
What peaks do the four spectra have in common? What peak(s) are found only in one or two of the samples?