NMRQA2

NMRQA2 contient des questions de révision et des réponses sur la spectroscopie RMN.

NMRQA2 is a 5 window App containing about a hundred and sixty seven simple revision questions and answers on NMR. This App is not intended for people who are not familiar with the basic concepts of NMR. Obviously it is not intended for NMR experts. It is intended for scientists and research students who are using NMR and want to check their knowledge of basic NMR facts, experimental parameters, signal processing, relaxation and methods of obtaining maximal signal-to-noise. NMRQA2 may also be useful for undergraduate students undertaking advanced courses on 1D-NMR. It only gives short single or two sentence answers and so it is not intended to replace textbooks or user manuals but it may help you understand them.

It does not contain the material covered in most undergraduate lecture courses or elementary texts and it is limited to 1D NMR. Its focus is on practical aspects. It is hoped it will help you interact with NMR operators and set up your own NMR experiments. There is a list of the topics covered below.

Topics include:-

Larmour frequency and NMR operating frequency.

Chemical shift.

Gyromagnetic ratio.

Locking and shimming.

Sensitivity and natural abundance 1H,13C,15N, 19F and 31P.

Pulse widths.

Coupling in 13C-NMR

Paramagnetic effects on signals.

18O isotope effects in 13C-NMR

T2 relaxation and optimum acquisition time.

Zero filling.

Signal-to-noise.

Folding and truncation.

Exponential multiplication and linebroadening.

T1 relaxation.

Ernst equation.

Optimising pulse rate and pulse angles.

Measuring T1 values using the progressive saturation technique.

Measuring T1 values using the inversion recovery technique.

Dummy scans.

Dipolar and CSA relaxation.

Effect of molecular size on dipolar and CSA relaxation.

Effect of magnetic field strength on dipolar and CSA relaxation.

Solid State NMR

Magic angle spinning

Cross polarisation

CPMAS

Dynamic Nuclear Polarisation (DNP) in solid state NMR

Temperature jump DNP

Dissolution NMR