3: 2D NMR experiments, Diffusion NMR & MRI

Question 1

Pulse-acquire has what format for processed data

Answer 1

one dimensional (frequency)

Question 2

Hahn-echo has what format for processed data

Answer 2

pseudo two-dimensional (frequency-time)

Question 3

CPMG has what format for processed data

Answer 3

pseudo two-dimensional (frequency-time)

Question 4

NOESY has what format for processed data

Answer 4

two-dimensional (frequency-frequency)

Question 5

EXSY has what format for processed data

Answer 5

two dimensional (frequency-frequency)

Question 6

properties two-dimensional NMR experiments are able to measure for a biomolecule

Answer 6

Primary, Secondary, and Tertiary structures, dynamics and binding kinetics

Question 7

what are the components of a 2D pulse in order

Answer 7

90 degree pulse, t1 delay, mixing time, acquisition

Question 8

The amplitude of a cross peak in a NOESY experiment is dependent on what

Answer 8

whether W0 or W2 process dominates

Question 9

What is the sign of cross peaks in NOESY experiments

Answer 9

either positive and negative

Question 10

What is the sign of cross peaks in EXSY experiments

Answer 10

only positive

Question 11

The amplitude of a cross peak in an EXSY experiment is dependent on what

Answer 11

the mixing time and the kinetics of exchange

Question 12

Pulsed gradient spin echo NMR spectroscopy uses what`

Answer 12

magnetic field gradients to spatially locate nuclei.

Question 13

In 2-dimensional spectroscopy, the Larmor frequency of protons is stored as

Answer 13

a signal intensity in the first dimension.

Question 14

The nuclear Overhauser effect can be used to determine what

Answer 14

through space interactions in a biomolecule.

Question 15

The diffusion-ordered spectroscopy (DOSY) experiment is based on what

Answer 15

a spin echo

Question 16

For two dipolar coupled nuclei, I and S, what are the possible pathways for the system to return to thermal equilbrium

Answer 16

W2 - increase in alpha states for S nuclei
W0 - decrease in alpha states for S nuclei

Question 17

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

Answer 17

10^-11 seconds

Question 18

In 2D EXSY or NOESY NMR, in a solution of deuterated chloroform, a negative cross peak is expected to be observed between

Answer 18

methyl and hydroxyl protons in ethanol

Question 19

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

Answer 19

methyl and hydroxyl protons in ethanol

Question 20

In an EXSY experiment would cross-peaks be expected to be observed for a solution of ethanol in deuterated chloroform.

Answer 20

nope

Question 21

The 2D data of a DOSY| experiement depends on

Answer 21

time and frequency

Question 22

what is the DOSY experiment based on

Answer 22

spin echo sequence

Question 23

the PGSE experiment measures what

Answer 23

self diffusion

Question 24

what does signal attenuation depend on in PGSE experiment

Answer 24

depends on the nucleus neing studied

Question 25

The probability distribution for the displacement of molecules through self-diffusion has what sort of distribution

Answer 25

Gaussian distribution.

Question 26

If the signal decay in a PGSE experiment is Fourier transformed, what is the result

Answer 26

a probability distribution of displacement.