Fig. 3.

Selective TOCSY experiment performed on another human urine sample with target excitation at 4.0 ppm. Note that the experiment establishes that one of the histidine beta peaks contributes, along with TMAO, to the peaks obscuring the high field taurine triplet peak at 3.28 ppm. The experimental set up was similar to that used for the experiment shown in Fig. 2. An IBURP 1 pulse was used to effect a 20 Hz selective excitation centered at 4.0 ppm indicated by the asterisk (*). A DIPSI 2 spinlock was applied for 40 ms. Histidine observed was endogenous in this sample