This article is a list of pulse sequences used in nuclear magnetic resonance spectroscopy.
| Name (acronym) | Backronym | Purpose | Article |
|---|---|---|---|
| Pulse acquire | The simplest sequence with which equilibrium magnetization is rotated to the transverse plane and the signal immediately recorded as a free induction decay | ||
| Spin echo | A simple sequence that refocuses the offset but not the coupling between two spins. Widely used as part of larger pulse sequences since it also allows to create coherence transfer which forms the basis of two-dimensional experiments | Spin echo | |
| COSY | COrrelation SpectroscopY | A two-dimensional technique that allows to identify which spins are coupled to each other: these will appear as cross peaks in the spectrum | COSY |
| ECOSY | Exclusive COrrelation SpectroscopY | A variant of COSY that accuratle measures small J-couplings | ECOSY |
| TOCSY | TOtal Correlation SpectroscopY | An improvement on the COSY sequence which permits to observe cross peaks between nuclei connected by a chain of couplings, hence joining up long chains of molecular fragments | TOCSY |
| INADEQUATE | Incredible Natural-Abundance DoublE-QUantum Transfer Experiment | Identifies couplings between adjacent spin-active atoms of low natural abundance, such as 13C | INADEQUATE |
| HSQC | Heteronuclear Single-Quantum Correlation spectroscopy | Detects correlations between two different nuclei separated by only one bond | HSQC |
| HMCQ | Heteronuclear Multiple-Quantum Correlation spectroscopy | Gives an identical spectrum to HSQC but using a different sequence, which can result in different quality spectra | |
| HMBC | Heteronuclear Multiple-Bond Correlation spectroscopy | Detect correlations between two different nuclei separated by more than one bond | HMBC |
| NOESY | Nuclear Overhauser Effect SpectroscopY | The cross peak now contain the resonances from nuclei which are close in space rather than in number of bonds, exploiting the Nuclear Overhauser effect | NOESY |
| ROESY (CAMELSPIN) |
Rotating frame nuclear Overhauser Effect SpectroscopY (Cross relaxation Appropriate for Minimolecules Emulated by Locked SPINs) |
Similar to NOESY but more useful in smaller molecules | ROESY |
| INEPT | Insensitive Nuclei Enhanced by Polarization Transfer | Improves the sensitivity of experiments on nuclei with small gyromagnetic ratios by transferring the magnetization from other nuclei coupled to them | INEPT |
| BIRD | BIlinear Rotation Decoupling | Distinguishes spins that are attached to a spin-active nucleus from the others (e.g. identifies protons attached to 13C from those bonded to 12C) | |
| TANGO | Testing for Adjacent Nuclei with a Gyration Operator | Exclusively excites transverse magnetization from spins bonded to a spin-active nucles (e.g. protons bonded to 13C | |
| HETCOR | HETeronuclear CORrelation Spectroscopy | Detects correlation between nuclei in the same manner as HMBC and HMQC but measures the signal on the heteronucleus which can lead to a lower sensitivity | |
| APT | Attached Proton Test | Permits to separate between signals deriving from carbons with an even versus an odd number of protons attached in Carbon-13 NMR by showing them as positive or negative peaks respectively. This simplifies the spectrum by allowing to decouple while retaining useful information on the nature of the carbon centre reference | APT |
| WATERGATE | WATER supression by GrAdient Tailored Excitation | Suppresses water signals which can be overwhelmingly large in proton NMR when H2O is used as the solvent reference | |
| CYCLOPS | CYCLically Ordered Phase Sequence | Improves the quality of the spectrum by repeating the experiment in such a way that the actual signals reinforce each other while the imperfections and errors cancel out. It is often used in conjunction with other sequences reference 1 and 2 | |
| DEPT | Distortional Enhancement by Polarization Transfer | Allows to display primary, secondary and tertiary carbons on either the positive or negative side of the spectrum, similarly to an APT, by the choice of an appropriate phase for the pulse. | DEPT |
References
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