Fig. 2.

Use of the Selective TOCSY experiment to isolate the peaks of the metabolite taurine from obscuring peaks in a human urine sample. Note that taurine peaks are completely obscured in 1D ¹H NMR spectrum (top two spectra), but cleanly isolated in the Selective TOCSY spectra. Selective TOCSY experiments used pulse sequence B shown in Fig. 1, employing an IBURP1 shaped pulse to effect a 25 Hz selective excitation centered at the frequency positions indicated by an asterisk (*), and a 35 ms DIPSI 3 spinlock. Experiments were performed at an endogenous taurine concentration of 0.4 mM. The unknown species labeled here as “U1” was subsequently identified as histidine (see Fig. 3)