1. Nuclear Magnetic Resonance Spectroscopy
(NMR)

2. Why NMR?
The most powerful and broadly applicable technique for structure determination
Provides the most information about molecular structure
1H NMR and 13C NMR are the most common

3. NMR in Peer Reviewed Papers

4. What is NMR?
Applying an external magnetic field

5. How is the External Magnetic Field Created?
It is created by a superconducting electromagnet

6. The NMR magnet is a coiled wire
Made of nobium and tin/titanium
Lots of current is running through it

7. Your sample is placed in the middle of a magnetic field
The lower the resistivity the higher the current
The higher the current the stronger the magnetic field

8. How do we achieve low resistivity?
The wire needs to be at supercritical temperature
This is extremely cold
If the wire goes below its supercritical temperature it has 0 resistivity

9. Nobium Niobium makes for a terrific superconductor
It has a high critical temperature compared to other elements on the periodic table at 9.25K

10. That means at that temperature its resistivity is exactly zero
It can handle lots of current to increase magnetic field strength
 Nb is bonded with tin or titanium (to make Nb3Sn or NbTi wire) to increase durability

11. Liquid Helium The magnet sits in the coldest substance on the planet
Liquid Helium is 4K
Liquid Nitrogen (77K) keeps this cold
The air conditioner (65 °C) keeps the LN2 cold

12. Safety Rules Do not turn off the air conditioner Wear a sweat shirt
If He rapidly boils it will throw the magnet off center
This is a QUENCH!
QUENCH = BAD
A quench repair on average is $18,000
Cost of NMR $350,000 - $800,000

13. NMR Probe
It’s “pulse” NMR because the console generates RF pulses orthogonally to the magnetic field
The probe delivers and receives them to produce a signal
Tune properly..but be careful with Tune and Match Rods (use red non-magnetic tool to turn)

14. Let’s run a sample

15. Quick Tips to Preserve Probe
Use the spacer tool
LFG - LISTEN FOR GAS when sample is at top of bore
Document all error messages
Try “ii restart” if you can’t wobb or lock
Try another “getprosol” if you can’t wobb or lock
If it’s not the machine it’s probably your sample (Is it the solvent? Is it fresh? Is the sample at optimal concentration?)

16. Quality Control Prevention is the best medicine Refurbished probe
New Console
New Software
Record error messages (led to updated firmware)
Write name on schedule
If you see something say something (24/7)

17. Quick Tips on NMR Tubes Wilmad 528-pp, 8 inch
Putting in oven too long can…..
….warp the glass

18. THINK: What can the NMR do for YOU?