The selective 1D COSY experiment permit to obtain 1D COSY spectra from which COSY patterns can be easily extracted and analyzed in terms of coupling constant values. Improved results are obtained from the gradient-based selective ge-1D COSY experiment.

Easy implementation on AVANCE spectrometers with selective excitation using shaped pulses.

The selective ge-1D COSY experiment consists of three parts:

Selective excitation of the selected resonance.

Evolution of homonuclear J-couplings during an optimized delay followed by a mixing 90º pulse for anti-phase polarization transfer to other spins (see COSY Block).

Proton detection as usual.

Similar modified approaches have been reported:

• The first published version of the selective 1D COSY experiment ( 86JMR106-70 ) used a single (90º or 270º) gaussian pulse as a selective excitation. A DANTE pulse train ( 96CONC119 ) has also been used.
• Addition of a refocusing delay and a Z-filter just prior to acquisition ( 86JMR106-70 ) in order to achieve in-phase magnetization.
• Using a chemical-shift-selective filter (CSSF) ( 88JMR548-76 , 88JMR582-78 , and 91TET3535 ).
• Using the DICE approach ( 90JMR331-87 ).
• Using the TSE-TSE (double-resonance two-spin effect) scheme ( 94JMRA246-107 , 95JMRA72-112 , 95JMRA273-116 , 95JMRA128-117 , 96JMRA90-119 , and 96JMRA145-119 ). The TSETSE  experiments offer a new form of correlation spectroscopy by applying two simultaneous soft pulses at two different chemical sites, converting in-phase absorption-mode magnetization into anti-phase dispersion-mode magnetization.
• Use of pulsed-field-gradients (see selective ge-1D COSY experiment).
• A selective 1D ¹³C COSY experiment has also been applied to ¹³C-labeled compounds ( 90MRC149 ).

The selective 1D COSY experiment can be run with minor changes from a predefined parameter set. Detailed description of the experiment can be found in the original publication ( 86JMR106-70 ). Two important parameters to consider are:

Selectivity of the selective excitation pulse: the user must define the shape, the duration and the power level needed for a defined excitation profile.

Optimization of the J-coupling delay as a function of 1/(2*J(HH)), in order to get the anti-phase magnetization of the selected proton suitable for transfer polarization.

For further details on practical implementation of selective 1D COSY experiments on AVANCE spectrometers see Tutorial: selective 1D COSY experiment.

In 1D COSY spectra, all coupled protons appear in antiphase pattern with respect to the active coupling of the selected proton and in-phase pattern with respect to all other passive couplings.
See Spectra of DBPA

An excellent review describing selective excitation in 1D and multidimensional NMR experiments was published ( 91MRC527 ).