Optimum tip angle and relaxation delay for quantitative analysis

Abstract

For the quantitative analysis of NMR spectra, the relationship between the tip angle and the relaxation delay is examined. It is shown that the common procedure of using a small tip angle combined with a short delay is not the optimum. Instead, an angle of approximately 83° with a pulse‐repetition period of 4.5 multiplied by the longest T₁ is the optimum procedure. However, the results obtained from this procedure are only slightly better than those obtained from the standard „90 ‐ wait 5T₁,”︁ method. It is further shown that the 83° angle is independent of T₁, but that the integral accuracy is relatively dependent on the estimate of T₁.