Archived App (Last seen on 5 Apr 2026)
This is an archived listing of the app previously available on the App Store.Although the app is no longer distributed by Apple, you can still view its description, screenshots, version history, ratings, and metadata for reference.
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About
NMRQA is an App containing about a hundred and sixty five 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. NMRQA 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. If you want to analyze pH dependent changes in chemical shift you may find the program "ppmfit" in the Mac app store useful. If you want to estimate the contributions of dipolar relaxation and relaxation by Chemical Shift Anisotropy(CSA) to carbon-13 T1 values you should find "T1calc" in the Mac app store useful.
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
Hyperpolarisation and MRI
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What's New in NMRQA
2.6
April 7, 2023
This is a minor update with new screenshots for 6.7 inch screens.
