Lab 7- NMR

Caitlin Verhalen
Instrumental Chemistry
Lab #7
Fourier Transform Nuclear Magnetic Resonance (FT-NMR)
The goal of this experiment was to investigate the operation of the FT-NMR by running standard
known samples and an unknown sample. A proton and C13 analyses was to be run for all samples. A 2D
analysis of the samples was to be examined as well. The samples used for this lab was olive oil, stearic
acid and the unknown.
The instrumentation of the FT-NMR works with a sample being placed in a strong magnetic field
and the nuclei that are affected by the field can be investigated. The nuclei in a magnetic field absorb and
re-emit electromagnetic radiation. This type of instrument is used in determining structures of organic
compounds, common in advanced medical techniques. Common spectra produced for the FT-NMR is for
the analysis of hydrogen and carbon atoms on a compound. The spectra produced from analyzing the
molecule is based on chemical shift, multiplicity and splitting. The structure of the compound is gathered
from this instrumentation and the placement of the carbon and hydrogen atoms in the molecule help to
analyze different organic compounds.
Procedure: FT-NMR
Preparing the sample
Add about 4 drops of sample if solid should be about 80mg, and to NMR tube then add 1ml of
chloroform of about 3-4 cm
 Cap the tube
 Label the NMR tube
 Check into NMR log book
 Wipe off the tube with a Kim Wipe without touching the bottom of the tube, hold near cap place
tube into blue spinner until the tube hits the bottom wood
 If the computer is not logged into click York College Chemistry
 Once computer is logged into, click on Topspin 2.1
 Click into command bar (pinkish bar)
 Type ej to eject blank place holder
 Remove place holder and place in you sample
 Type ij to inject the sample
 Type ro on
 Type New and put the experiment parameters
 Select solvent (Ex. CDCl3)
 Select C13, H1, C13 APT
 Type rsh into the command box, select shim file most recent for your solvent
Type lock and select solvent
Type bsmsdisp to begin shim
Click Z, Z2 and start the play with the (+) of (-) the red/green line will raise or lower, you want it
at its highest point before falling back down
Type eda
Type zz (this will run sample)
When finished type ft
Type apk
Integrate for H1, and pick peaks for both C13 and H1
Type ro off
Type lock off
Type ej to eject sample
Insert place holder and type ij to inject place holder
Method Day 1: FT-NMR
We ran standard samples of stearic acid and olive oil
o Proton + 13C_ATP analysis of stearic acid
o Proton analysis of olive oil was only ran today
We did not get enough time to do 13C_ATP of olive oil or our unknown on the first day
Method Day 2: FT-NMR
We finished the olive oil and ran a 13C_ATP scan of it
We ran the H proton + the 13C_ATP of the unknown A sample
o Computer continuously kept showing an error saying No Data File selected when we
tried to enter ZZ
 We had to go to file clicked on our active file and entered zg instead, then the
acquisition begun.
2D analysis was ran for all samples except the unknown kept coming up displaying the same
peaks as the last sample- stearic acid
Data: All spectra can be found in Instrumental Notebook
By working with this instrument we were able to increase our knowledge of the NMR. We had
previously worked with the NMR briefly in organic chemistry; however we did not run multiple samples
and fully grasp the operation of this instrument until now. The samples were analyzed successfully and
more would have been analyzed if the 13C_ATP did not have such a long run time. When comparing the
spectra the unknown seemed to have similar peaks to the olive oil spectra, indicating that compound
structure of the unknown was more relatable to olive oil instead of stearic acid. The FT-NMR did not give
us any problems when conducting each analysis however, when we attempted to run the 2D analysis each
spectra continued to show up the same as stearic acid, there was a possible error when switching to 2D
analysis that enabled us to view them correctly.