3: 2D NMR experiments, Diffusion NMR & MRI Flashcards
Pulse-acquire has what format for processed data
one dimensional (frequency)
Hahn-echo has what format for processed data
pseudo two-dimensional (frequency-time)
CPMG has what format for processed data
pseudo two-dimensional (frequency-time)
NOESY has what format for processed data
two-dimensional (frequency-frequency)
EXSY has what format for processed data
two dimensional (frequency-frequency)
properties two-dimensional NMR experiments are able to measure for a biomolecule
Primary, Secondary, and Tertiary structures, dynamics and binding kinetics
what are the components of a 2D pulse in order
90 degree pulse, t1 delay, mixing time, acquisition
The amplitude of a cross peak in a NOESY experiment is dependent on what
whether W0 or W2 process dominates
What is the sign of cross peaks in NOESY experiments
either positive and negative
What is the sign of cross peaks in EXSY experiments
only positive
The amplitude of a cross peak in an EXSY experiment is dependent on what
the mixing time and the kinetics of exchange
Pulsed gradient spin echo NMR spectroscopy uses what`
magnetic field gradients to spatially locate nuclei.
In 2-dimensional spectroscopy, the Larmor frequency of protons is stored as
a signal intensity in the first dimension.
The nuclear Overhauser effect can be used to determine what
through space interactions in a biomolecule.
The diffusion-ordered spectroscopy (DOSY) experiment is based on what
a spin echo
For two dipolar coupled nuclei, I and S, what are the possible pathways for the system to return to thermal equilbrium
W2 - increase in alpha states for S nuclei
W0 - decrease in alpha states for S nuclei
In 2D EXSY or NOESY NMR, Ethanol, in a 0.001 M solution in D2O, has a rotational correlation time,
tau(c) on what order
10^-11 seconds
In 2D EXSY or NOESY NMR, in a solution of deuterated chloroform, a negative cross peak is expected to be observed between
methyl and hydroxyl protons in ethanol
In 2D EXSY or NOESY NMR, in a solution of deuterated ethylene glycol, it is possible for a positive cross peak to be observed between
methyl and hydroxyl protons in ethanol
In an EXSY experiment would cross-peaks be expected to be observed for a solution of ethanol in deuterated chloroform.
nope
The 2D data of a DOSY| experiement depends on
time and frequency
what is the DOSY experiment based on
spin echo sequence
the PGSE experiment measures what
self diffusion
what does signal attenuation depend on in PGSE experiment
depends on the nucleus neing studied
The probability distribution for the displacement of molecules through self-diffusion has what sort of distribution
Gaussian distribution.
If the signal decay in a PGSE experiment is Fourier transformed, what is the result
a probability distribution of displacement.
