MEASUREMENT OF SPIN-LATTICE RELAXATION-TIMES IN SYSTEMS UNDERGOING CHEMICAL-EXCHANGE

A new method is presented for measuring spin-lattice relaxation times in systems with chemical exchange. The method is based on an analysis of the effect of exchange on saturation factors. Unlike the inversion- recovery method with saturation, our experiment does not require selec tive excitation; it also does not require a fit of data to a multiple- exponential model, in contrast to inversion recovery without saturatio n. A number of variations of the experiment are presented, which are a pplicable to different regimes of T-1 and exchange-rate values. The me thods are demonstrated for the creatine kinase reaction in an in vitro sample. (C) 1994 Academic Press, Inc.