NMR Technology

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NMR Technology
Qualion NMR

• The analytical measurement principle

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What is ¹H NMR?

• Hydrogen Nuclear Magnetic Resonance
• Provides picture of the hydrocarbon structure,
  from which we determine physical and chemical
  information
• Non invasive like MRI, therefore all samples can
  be returned back to the process.
• Heavy opaque or dark materials easily analyzed
• Technology developed since 1950s

MRI
Magnetic Resonance Imaging
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What is ¹H NMR Analysis?

• NMR Nuclear Magnetic Resonance
• Nuclear - NMR looks at the nuclei of molecules
  (protons-neutrons)
• More specifically at their nuclear spin
• Some nuclei have a magnetic moment due to that
  spin (behave like a small magnet)
• Most important, nuclei are 1H ,13C,19F and 31P
• ¹H-NMR is looking at ¹H-protons in molecules,
  excellent for hydrocarbon analysis

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The Electromagnetic Spectrum
SPECTROSCOPY ANALYTICAL
TECHNOLOGIES
X-ray UV VIS IR
Microwave ESR NMR
NMR spectroscopy uses radio-waves to interact
with samples
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¹H Proton Magnetic Moment (M)
Hydrogen Atom (Proton)
M

Proton is spinning
Magnetic moment (M) generated
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Nuclear Spins and Magnetic Fields
In a strong magnetic field (Bo), magnetic moments
M align along Bo

• With no magnetic field,
• magnetic moments M are
• randomly oriented

S
M
M
M
N
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Alignment and precessing of M

• Magnetic Moments Align and Precess
• at a Frequency wo

Bo
N
S
S
Wo
wo is proportional to the Bo size
e.g. Bo 1.35 Tesla wo 57 MHz
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Bulk Magnetic Moment M0
Precessing spins can be described as a bulk
magnetic moment Mo
Bo
N
S
Mo
Mo Summation of individual magnetic moments
of all protons in the sample
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Re-align to a second magnetic axis
RF pulse is turned on for 4-20 microseconds and
generates a second magnetic field B1
RF _at_ 57 MHz
Bo
S
N
Mo
B1
Magnetic field B1 causes Mo to move and re-align
to the second magnetic axis
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Re-align to original magnetic axis
The protons relax and re-align to their original
equilibrium position along Bo Axis
FID
RF _at_ 57 MHz

• When RF Pulse ends

Bo
S
N
Mo
B1
Relaxation of Mo generates an RF current that
is picked by the irradiation coil A decay
signal is generated, called Free
Induction Decay signal (FID)
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Measurement in a NMR Process analyser
Top View
Magnet
Flow Pipe Probe
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NMR permanent magnet technology
Current passed through wire gradients
creates shaped magnetic fields that are used to
straighten field lines
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Fast Fourier Transform- FFT
Time domain signal
Frequency domain signal
Free Induction Decay(FID)
NMR Spectrum
F.F.T.
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Chemical Shift in NMR spectra

• How does the NMR resolve the different protons in
  the spectra ?
• Each proton in a different chemical environment
  (bond) senses a different magnetic field BX due
  to the shielding created by surrounding electrons
  
• More electrons more shielding

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Protons in different chemical environment
S
Proton
Proton
N
External applied field Bo
Actual field at protons
electron
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Difference in sensed magnetic field

• Due to a difference in the sensed magnetic
  field,
• protons A and B precess at a different frequency
  WA and WB

Bo
BA
N
S
BB
S
WA
WB
wA and wB are proportional to the size of BA and
BB
The precessing frequency becomes the fingerprint
of the chemical environment of the different
protons
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From FID to results
Frequency domain signal
Time domain signal
Fast Fourier transform
NMR Spectrum
Free Induction Decay(FID)
Chemometric calibration models
Results
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Thank you!

• Contact us
• QUALION NMR  ANALYZERS Advanced Technology
  CenterBuilding 22, P.O.B. 15017 Haifa 31905
• Israel  Tel  [phone]Fax  (972)
  4-855 1162Email  info_at_qualion-nmr.comWeb 
  www.qualion-nmr.com