University of Ottawa NMR Facility Blog: BLOG Index

Wednesday, March 4, 2015

BLOG Index

University of Ottawa NMR Facility BLOG INDEX

March 2015

17O NMR of liquids

H20 vs D2O

1D selective HOESY

1H-19F

1H-31P

1D selective NOESY measurements

for exchanging roramers

1D TOCSY measurements

as a function of mixing time

for mixture analysis

1H NMR with X nucleus decoupling

1H[11B]

1H[13C]

1H[19F]

1H[27Al]

1H[31P]

2D correlation spectroscopy (COSY)

11B COSY

COSY 90 vs COSY 45

double quantum filtered

ECOSY for measurement of coupling constants

magnitude vs phase sensitive

vs TOCSY

2D exchange spectroscopy (EXSY)

and NOE (1)

and NOE (2)

2D heteronuclear Overhauser measurement (HOESY)

better data – more scans or more slices?

data apodization

phasing (video tutorial)

2D NOESY measurements

19F NOESY

and exchange (1)

and exchange (2)

choice of mixing time

effect of viscosity

phasing

phasing (video tutorial)

small vs large molecules

2D ROESY measurements

2D total correlation spectroscopy (TOCSY)

HSQC - TOCSY

TOCSY vs COSY

2H decoupling

2H NMR of liquids

chemical shift referencing in

on Bruker AVANCE spectrometers

Acoustic Ringing

backward linear prediction to correct for

pulse sequence to minimize

ASCII file generation

in TOPSPIN (1)

in TOPSPIN (2)

B1 Homogeneity

Background signals

11B

23Na

from dirty NMR probe

Background suppression

11B in liquids

11B in solids

Baseline correction

improving

in 2D NMR spectra

in solids MAS spectra of quadrupolar nuclides

Benchtop NMR

(1)

(2)

BIRD filter

Bloch decay vs Cross polarization

Chemical equivalence

Chemical exchange agents for spectral simplification

D2O shake

trifluorocaetic acid

Chemical shift referencing

1H in aqueous solution

external

in 2H NMR

Chemical shift tensors

and MAS sideband manifolds (1)

and MAS sideband manifolds (2)

effect of sample grinding on the measurement of

from static CP spectra

measurement from static solids spectra

Chemical shifts

concentration dependent

solvent effects – improving chemical shift resolution

temperature dependent

Concentration gradients

effect on spectral quality (1)

effect on spectral quality (2)

Coupling

13C – 14N

13C-14N-31P

13C – 19F

13C – 2H (1)

13C - 2H (2)

13C – 2H (3)

13C - 59Co

coupling between magnetically equivalent nuclei

signs of coupling constants vis ECOSY

virtual

Cross polarization for solid and CPMAS

CPMAS of household dust

effect of contact time

effect of MAS spinning speed

effect of quadrupolar nuclides on spin I = ½ nuclides (1)

effect of quadrupolar nuclides on spin I = ½ nuclides (2)

field dependence of chemical shift resolution in

importance of Hartman-Hahn match

in relation to MAS and high power decoupling

measurement of 13C 90 degree pulses with

measurement of relaxation times with

optimizing 1H decoupling in

ramped contact pulses

sensitivity improvement from

to distinguish solid polymorphs

vs Bloch decay

with FSLG HETCOR

Cross polarization with dipolar dephasing for solids

as an assignment tool

effect of spinning speed

with long dephasing delays (1)

with long dephasing delays (2)

Decoupler pulse calibration

in liquids

in solids

Decoupling

1H and 31P decoupling

1H decoupling and 13C signal-to-noise ratio

1H decoupling and 31P signal-to-noise ratio

11B decoupling

13C decoupling

19F decoupling

2H decoupling

27Al decoupling

31P decoupling

high power 1H decoupling in solids

homonuclear decoupling

modes of heteronuclear decoupling in liquids

DEPT

and quaternary alkyne carbon sites

APT vs DEPT 135

effect of 1H tuning on

missing signals in

of “acetone-d6”

of “perdeuterated “ solvents

vs DEPTQ

with 29Si

DEPTQ

vs DEPT

Diffusion and DOSY

diffusion in CPMG measurements

DOSY

Digital Filtering

Double presaturation

Dummy scans

Dynamic nuclear polarization (DNP)

Dynamic processes studied by 1D NMR

exchange studied by saturation transfer

exchanging rotamers

the NMR time scale

Earth’s field NMR

Echoes

CPMG

Fourier transform of

gradient spin echoes and selective excitation

simple spin echo

to remove 11B background in solids

Exponential line broadening

tutorial video

tutorial video

Floor vibrations

effect on NMR spectra

Food and drink

candy cane

coffee

fruit cake

popcorn

rum and eggnog

shortbread cookies

Free induction decay

effects of truncation

Frequency shifted Lee-Goldberg CP-HETCOR for solids (CP-FSLG HETCOR)

Heat dissipation in Bruker spectrometers

Heteronuclear double quantum filter

HMBC experiments

HMQC responses in HMBC spectra

measuring 19F – 13C coupling in 1H - 13C HMBC

missing signals in

Nyquist fold-backs in

HMQC, HSQC and edited HSQC experiments

1H – 11B

19F – 13C

31P -109Ag

31P – 13C

doubled signals / poor decoupling

HMQC vs HSQC

HSQC - TOCSY

HSQC vs edited HSQC

isotope effects in 19F – 13C HMQC

multiple bond or weak one-bond correlations in

removing t1 noise in

Homonuclear 1H decoupling

Bloch-Siegert shifts

broadband 1H decoupled 1H spectra

iPad / iPhone apps

Bruker Almanac

educational

Stanford University course on Fourier transforms vis iTunes U

Isotope effects

acetone

chloroform

complexed solvents

ethane

in 19F – 13C HMQC

methylene chloride

“perdeuterated” solvents

triphenyl phosphate

water

Kinetic measurements

Lineshape specification

erroneous

Linear prediction

backward

backward LP to correct for receiver overload

forward

forward LP for 2D data

Liquid crystalline samples

Lock

consequence of locking on the wrong solvent

how high should the lock signal be?

paramagnetic samples

spectra acquired with a sweeping field

spectral distortion from weak lock signal

Varian

Magic angle spinning for solids (MAS)

1H MAS

and available rf field

effect on Hartman-Hahn match

field dependence of chemical shift resolution

how fast to spin

how much sample

increasing signal-to-noise ration in

setting the magic angle (1)

setting the magic angle (2)

solution vs MAS spectra

rotor crashes

Magnet

accessing a used magnet

measurement of field drift

quench

Magnet cryogen fills and spectral quality

helium fills

helium one-way valve oscillation

nitrogen fills

nitrogen pressure in the magnet

Magnetic equivalence

Magnetic resonance imaging (MRI)

gradient calibration / 1D MRI

MRI photocopier

Nyquist fold-backs in MRI images

slice selection

why MRI scanners are loud

Measurement of long range C-H coupling constants

NMR acronyms

NMR of more than one isotope

23Na and 51V

NMR spectra without pulses

NMR spectrum frequency scale

NMR spectrum of dust (13C CPMAS)

NMR spectrum of hand cream (1H and 13C)

NMR spectrum of natural gas (1H)

NMR spectrum of TMS (1H)

NMR time scale

NMR tube thickness

NOE’s and decoupling

negative NOE’s and decoupling

positive NOE’s and decoupling

Nyquist fold-backs

and digital filtering

and mode of data acquisition

in HMBC data

in MRI

used to enhance satellite transitions in quadrupolar nuclides

Paramagnetism

13C spectra of paramagnetic compounds

determination of paramagnetic susceptibility

establishing the 2H lock for paramagnetic samples

paramagnetic shifts

the effect of paramagnetic oxygen

Phase of an NMR spectrum

first order phase errors

phasing a 1D spectrum (video tutorial)

phasing a 2D spectrum (video tutorial)

Probes

broadband vs inverse broadband

coil geometry

solids

why so expensive

Probe arcing

Probe tuning and matching

effect of 1H tuning on 13C spectra

effect of cable length

effect of sample spinning

effect on 90 degree pulse

probe electronics

problems with salty samples

Pulse calibration

effect of probe tuning

fast determination

for shaped pulses

for spin I = n/2 quadrupolar nuclei in solids

measurement of 13C pulses using cross polarization in solids

Pulse power measurements

expressed in dB Bruker vs Varian

expressed in Hz

pulses

Pulsed field gradients

calibration

dephasing ability

gradient spin echoes

recovery times

Purge pulses

QCPMG measurements

distortions in QCPMG spectra

for solid state 2H NMR

Quadrature detection

Quadrature images

Quadrature spikes

how to remove

Quantitative 1H NMR

Quantitative 13C NMR

finding lost 13C signals

Radiation damping

Receiver gain

and signal-to-noise ratio

backward LP to correct for receiver saturation

distortion from mis-setting

Relaxation

effect of paramagnetic oxygen

faster relaxation time measurements in solids

relaxation differences used to resolve overlapping signals

T1 anisotropy in solids

T1 measurement

T1r

T2 CPMG filter to enhance sharp lines

T2 measurements and diffusion

T2 vs T2*

Residual 1H signals for benzene-d6 and chloroform-d

Resolution enhancement

by using benzene as a solvent

Retrieving empty spinners from NMR magnets

Sample limitation

making the best of

Saturation transfer measurements

Scans

and signal-to-noise ratio

Shaped pulses and selective excitation or broadband inversion

broadband 180 degree pulses

calibration

excitation profiles (1)

excitation profiles (2)

for selective excitation

Shimming

effect of concentration gradients

effect of sample depth

effect of sample mixing

effect of sample volume

effect of variable temperature gas composition

line shapes resulting from bad shimming

without a lock signal

Sinc distortion

Slice selection

Software for data processing

Solid polymorphs

Solid state 1H NMR

1H spin pairs

Solid state 2H NMR spectroscopy

echoes and Fourier transforms

increasing signal-to-noise ratio

measuring spectral parameters

QCPMG

T1 anisotropy

to determine molecular motions

Solid state NMR vs solution state NMR

Solid state NMR using a probe for liquids

Solid state NMR spectroscopy of quadrupolar nuclides with spin I = n/2

90 degree pulse calibration

baseline correction

enhancement of satellite transitions via the Nyquist sampling theorem

field dependence

Fourier transform of a single rotational echo

satellite transitions

Solution state NMR vs solid state NMR

Solvent effects

improving resolution

Solvent suppression

absolute water suppression

double presaturation

presaturation

watergate

watergate vs presaturation

Spin locking pulses

Spin simulations

butane

ethane

isopropyl groups

quadrupolar line shapes in solids (QUEST)

virtual coupling

Spinning liquid samples

Spinning sideband suppression in MAS spectroscopy

Steady state scans

t1 noise removal in 2D spectra

heteronuclear (tutorial video)

homonuclear (tutorial video)

Textbook recommendation

Thermal noise

TRAPDOR measurements

Triple resonance experiments

13C [2H][1H]

13C [31P][1H]

31P -13C HMQC with 1H decoupling

Variable temperature measurements

temperature calibration (1)

temperature calibration (2)

temperature dependent chemical shifts

temperature gradients

variable temperature gas composition and spectral quality

variable temperature to improve resolution

Video lectures

Video commentary by NMR experts

Video tutorials

1D spectrum phasing

2D spectrum phasing

exponential line broadening

EZ NMR

removing t1 noise from heteronuclear 2D spectra

removing t1 noise from homonuclear 2D spectra

Virtual coupling

Zero Filling

and throwing away noise

7 comments:

university said...: A debt of gratitude is in order for conveying all the supportive data throughout the years!; July 13, 2015 at 8:30 AM
membrane protein said...: Thanks for sharing us these information!; October 19, 2015 at 5:37 AM
Anonymous said...: Dear Glenn

I have an issue with low content impurities in the presence of a main ingredient, so I would know which is the dynamic range for my experiments on a Bruker Avance 400 MHz equipped with 16 bit ADC.
I mean which is the minimum signal area that is detectable in presence of a major peak, number of scans are not a problem but I'm afraid that the higher signal could flatten the smaller one.

Thank you very much

Anna; September 6, 2017 at 4:12 AM
Glenn Facey said...: Anna,
The dynamic range is very instrument and hardware dependent. It also depends on the way in which digital filtering and oversampling are used as well as the receiver gain used. If you need an accurate determination of the dynamic range, I recommend that you contact Bruker with the specific details of your instrument and data collection methods.

Glenn; September 6, 2017 at 9:31 AM
Unknown said...: Hello Prof. Glenn Facey,
I am working with HR-MAS NMR, 400 MHz (BRUKER), I have problem to shim the magnet, shimming is not working completely, I used the preliminary shimming results too,even the LOCK SIGNAL doesn't change it's position neither up nor down. Actually I changed the rotor, sample to sample, solvent, probe and set again, restart the BOSS, restart the whole system but in vain.
Spinning rate, 5kHz
Temperature, 23 C.

You kindly have any recommendation(s) ? please.; January 23, 2018 at 10:12 AM
Glenn Facey said...: Ali Sher,
Does adjusting the shims have any effect at all? If the shims are having absolutely no effect, I would check the connections at the shim power supply and at the base of the shim set in the magnet. Are the connections good? Perhaps you have a problem with the shim power supply.

Glenn; January 23, 2018 at 3:17 PM
Unknown said...: Thanksgivings dear Prof. Glenn Facey, for your great & in no time response, actually I checked all the connections too, which sound well connected and adjusted certainly there is no effect towards shimming. Might be it'd have certain potent problem, we are fighting to identify and solve.

Gratefulness once even more...
Best wishes.; January 26, 2018 at 9:16 AM

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