FT-NMR
Nuclear Magnetic Resonance (NMR) is a technique that exploits the magnetic
properties of certain atomic nuclei to determine physical and chemical properties of
atoms or the molecules in which they are contained. Most frequently, NMR
spectroscopy is used by chemists to investigate the properties of organic molecules,
but it is applicable to any kind of sample. The instrument measures the intensity of
the peak versus the concentration in ppm.
The instrument we will be using is a 300 MHz, 7.05 tesla and uses Fourier
transform to change the raw data into data of frequencies.
Purpose:
In this experiment, we hope to continue our learning process for this
instrument. Our goal is to successfully run a 2D experiment.
SOP of NMR
1. Making NMR tubes
 Take a small glass pipette and insert the tip into the solvent
o The solvent should include 80mg of solid or 4 drops of liquid
with 1mL of CDCl3
 Place the pipette in the opening of the NMR tube
o Collect about 4cm of solvent in the NMR tube
 Cap the NMR tube
2. Software
 Click on York Chemistry
 Click on Topspin 2.1
 Type ej in pink command line to eject the placeholder
o All commands are typed in pink command line at bottom of the
screen
 Place prepared NMR tube in the instrument
 Type ij to inject the sample
 Type ro on to turn on spinning
 Type new
o Fill in name, exp #, pro #, dir, and user
o Look at user manual to determine what information to put in
these lines
 Select solvent (CDCl3)
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Select experiment type
o Either proton or carbon ATP
Type rsh to select shim file
o Select most recent shim file (CDCl3)
Type lock
Select the solvent from the list (CDCl3)
Type bsmsdisp to start shimming
o Click on z and adjust +/- until the line is at its max
o Then click on z2 and adjust +/- until line is at its max
o Minimize screen
Type eda to open experiment parameters
Type zz to aquire data
After the sample is done running type ft for fourier transform
Type apk to automatically phase spectrum
Type abs to adjust baseline
Integrate and peak pick
o Follow instrument manual
Print spectra
Type ej to remove sample
Follow same protocol for each NMR sample
Day One:
Samples were prepared:
 Vegetable Oil
 Extra Virgin Olive Oil
 Peanut Oil
 Unknown A
13C APT, 1H and 2D spectra were collected for the vegetable oil sample
A 2D spectrum was run for extra virgin olive oil.
Day Two:
13C APT and proton graphs were made for the remaining peanut oil and unknown
samples. The 13C APT was also run for extra virgin olive oil. 2D spectrums could not
be obtained due to time constraints.
Conclusion:
NMR is a useful technique in a variety of different molecules and the identification
of unknowns. However, the vegetable oil graphs were difficult to interpret because
the structure is just reoccurring chains of hydrocarbons attached to a carboxylic
acid group. Although we were not able to label every peak on each graph, there is
enough evidence to suggest that unknown A is vegetable oil. They contain similar
peaks at similar intensities.
The biggest difficulty of this lab was the time constraints we had when using
the NMR. We were able to change the scans for carbon to 256 to provide a shorter
time but the 2D took an hour and we were not able to collect a 2D spectrum for
every sample. However, this was not an issue because the 2D was essentially just a
“check” to make sure that each carbon and proton spectrum matched.