NMR Lab Report
Introduction: NMR stands for Nuclear Magnetic Resonance. It is a process where atoms are put
in a magnetic field and then exposed to a second magnetic field producing an image with peaks
that represent the various carbons or hydrogen’s in a compound. The spin inside the nucleus of
an atom causes this signal to occur. NMR exploits the magnetic field of an atoms nucleus to
determine their chemical and physical properties. The two types of NMR are Carbon-13 and 1HProton. Solids and liquids can be used for NMR but majority of the samples that are run are
liquids. This is similar in a way to IR and Raman because it produces a spectrum that is used to
determine the chemical properties of a certain compound or an unknown and then compare it to a
known structure.
Purpose: The purpose of this experiment was to determine the properties and compound of an
unknown ratio sample. To do this we used several known samples and at the end compared them
to the unknown ratios to see how much of each known was in it.
Procedure:
Day 1: Become familiar with the NMR and, prepare samples, and start running known
standards on the instrument. Load the sample and follow the detailed instructions provided to
work the software on the computer. Run both a C-13 and 1H- proton scan of the samples. We
were only able to get one C-13 scan completed due to time constraints and choosing the wrong
C-13 scan as well as not preparing the samples right at first. We had to remake all the samples
because we forgot to include the solvent, CDCl3 .
Day 2: This day was more successful than the first day. After figuring out the right C-13
scan to perform we were able to get the rest of the samples and scans completed which included
our unknown, olive oil, vegetable oil, and peanut oil. After completing all the scans, the rest of
the time was spent figuring out how to read and determine what our unknown consisted of and
how much of each was in the unknown.
Conclusion: All spectra for this experiment can be found in the lab notebook. The experiment
was overall successful. After having some minor mishaps in the beginning we were able to figure
out how to work the instrument and determine the make-up of our unknown. There were two
unknowns to choose from and we chose unknown A. After conducting all the samples it was
found that we didn’t need to perform olive oil scans because the unknowns was only made up of
vegetable oil and peanut oil in different ratios. Unknown A being a certain ratio while unknown
B was the opposite of that. To determine what our unknown was made up of we compared the C13 and 1H-proton scans of the unknown, vegetable and peanut oil. It was found that our
unknown had more vegetable oil than peanut oil based on certain peaks from the unknown
spectra. This showed that there were peaks found in this spectra that were present in the
vegetable oil but not in the peanut oil. For example in the 1H-proton scan it is clearly seen that at
4.8 there is a peak present that is not found on the peanut oil sprecta as well as a small triplet
around 1.0 that is absent from the peanut oil scan. Based on these certain peaks we determined
that the ratio is around 60:40 or 70:30, vegetable oil to peanut oil respectively. There was no way
to determine the exact ratio of the oils, so this is just an assumption that we believe the ratio is
close to.