Transcript Lecture 9: The big picture

Fast Course in NMR
Lecture 9
Jan/Feb, 2016
Big picture
• 1D
• Review of how we do it
• Why 2D?
• What information does 2D give?
A. S. Edison
University of Georgia
2016
Human Urine
Bouatra et al:
Estimate at least 3079 compounds
A. S. Edison
University of Georgia
2016
NMR Implementation
Very Strong Magnet
Probe
http://wwwnmr.pharmazie.uni-marburg.de/www/jeol_magnet/fig6.jpg
~400,000x Earth’s magnetic field
Up to 14x greater than average MRI magnet
The NMR console is a radio
transmitter and receiver
A. S. Edison
University of Georgia
2016
Common Coils for NMR Probes
The basic requirements for a probe are that it has an electrical conductor oriented to
deliver a magnetic field B1 that is perpendicular to the static field B0.
Standard coil for 1H
Flow probe: Protasis
Standard coil for X nuclei
Solenoid
Alderman-Grant coil
Saddle Coil
Side view of
single pair
Top view of HTS probe
layout for 4 nuclei
HTS coils
Jason Kitchen (NHMFL) kindly provided the wire drawings
A. S. Edison
University of Georgia
2016
The nuclear spins induce an oscillating
voltage in the coil
A. S. Edison
University of Georgia
2016
The anatomy of 1D 1H NMR
This urine spectrum arises from 10s to several 100s of simpler spectra
A. S. Edison
University of Georgia
2016
A. S. Edison
University of Georgia
2016
J-coupling
doublet
For spin ½, splitting at one nucleus is i+1 where i is
the number of 1Hs at coupled nucleus
quartet
Coupling occurs up to about 3 chemical bonds
A. S. Edison
University of Georgia
2016
Phenylalanine
10
8
6
4
Chemical Shift
2
0
A. S. Edison
University of Georgia
2016
A. S. Edison
University of Georgia
2016
NMR is quantitative
(when done with full relaxation)
Urine is much more complicated!
A. S. Edison
University of Georgia
2016
2D NMR
• Reduces overlap in complicated spectra
• Provides a lot of additional information
through correlations
• Can ID molecules de novo using 2D NMR
• Can be used as a basis for database matching:
COLMAR
A. S. Edison
University of Georgia
2016
2D TOCSY spectrum of human urine
A. S. Edison
University of Georgia
2016
TOCSY and 1D
A. S. Edison
University of Georgia
2016
Information Content of Common 2D
NMR Experiments
COSY (Correlation Spectroscopy): J coupling (generally up to 3 covalent bonds)
TOCSY (Total Correlation Spectroscopy):
J coupling along coupled networks
Blue is one TOCSY network, green is another
HSQC (Heteronuclear Single Quantum Correlation):
Directly bonded 13C-1H or 15N-1H
HMBC (Heteronuclear Multiple Bond Correlation):
2 or 3 bond 13C---1H or 15N----1H
NOESY (Nuclear Overhauser Effect Spectroscopy)
Or ROESY (Rotating Frame Overhauser Effect Spectroscopy):
1H to 1H distances up to 5-6 Å
A. S. Edison
University of Georgia
2016
Using 2D NMR to ID Metabolites
COSY spectrum
A. S. Edison
University of Georgia
2016
This chain is almost symmetric.
How do we know which end is which?
A. S. Edison
University of Georgia
2016
HSQC
HMBC
Working with multiple 2D
datasets.
COSY
COSY
A. S. Edison
University of Georgia
2016