Selective detection of biexponential relaxation in isotropic solutions by mixed coherence filtering NMR

This is a trial to simplize sequences to get the relaxation function f31(t), which is usually detected by the double- or triple-quantum filtered (DQF or TQF) NMR in an isotropic phase. The results indicate that only two phase cycling is needed to get the f31(t) function, which shows the advantage of S/N (signal-to-noise ratio) in a minimum acquisition time. The filtering of coherence levels in the creation time need not be limited to double- or triple-quantum coherences. An 87Rb signal from a 4% (w/w) agar powder in 500-mM RbCl solution is recorded at 130.9 MHz as a Larmor frequency using a Bruker MSL 400 spectrometer.