Two-dimensional NMR

The development of two dimensional NMR in the 1970s was probably the greatest advance in the history of the technique. The addition of another dimension to NMR spectra expanded the types of information obtainable and made possible the vast array of tailored multi-dimensional experiments available today. The development of two dimensional experiments relied upon the introduction of pulsed NMR and the use of the fourier transform to process the data. To generate two dimensional data a variable delay between two pulses must be used. Incrementing the variable delay allows chemical shift information to be regularly sampled and later processed with the fourier transform to give a second dimension. Read on for more details.

ASAP - Acceleration by Sharing Adjacent Polarization

NMR is a non destructive technique and so reducing acquisition time can be used either to increase sample throughput, or to lower the detection limit. To lower the detection limit a given amount of time is used to acquire a greater number of scans than would normally be acquired. A relatively recent method for reducing acquisition time is ASAP (Acceleration by Sharing Adjacent Polarization)¹. The ASAP technique speeds acquisition by greatly reducing the length of the relaxation delay.