Simultaneous convection compensation and solvent suppression in biomolecular NMR diffusion experiments

Thermal convection and high intensity solvent resonances can significantly hamper diffusion estimates in pulsed gradient spin-echo nuclear magnetic resonance diffusion experiments on biomolecule samples. To overcome these two problems, a new double functional NMR diffusion sequence, double echo PGSTE-WATERGATE, is presented. The new sequence provides excellent convection compensation and solvent suppression (with a suppression factor in excess of at least 105 in a single scan) in biomolecular NMR diffusion experiments. Due to its stimulated echo nature, the new sequence is much less susceptible to spin-spin relaxation than Hahn spin-echo based sequences. Furthermore, the new sequence is not susceptible to spin diffusion due to the application of bipolar pulsed gradients. The new sequence is also much easier to set up compared to previously developed stimulated echo based convection compensation and solvent suppression sequence. The utility of the new sequence is demonstrated on an aqueous lysozyme sample.