Structure Elucidation - Validation of Identity of Choline

The HSQC NMR experiment proposed that the unknown metabolite is choline. In a follow-up experiment the structure identity was verified by a spiking experiment. Thereby choline is spiked to a sample of group 2. As the signals of interest were increased and no additional signals appeared, it could be verified that the corresponding metabolite is choline.

Series of 1H-NMR spectra for the verification of the proposed metabolite choline. The first row shows a spectrum of a control animal and the second row shows a spectrum of a sample of group 2. when comparing these two spectra it is obvious that choline is siginificantly increased for the sample of group 2. Choline is an endogenous metabolite, which is also slightly visible for the control sample. The third row shows a spectrum of choline in buffer. It is visible, that the peaks show the same chemical shift like the significantly increased peaks of the sample of group 2. The last spectrum (fourth row) shows the spectrum of the sample of group 2 (second row) with additonal choline spiked. When comparing the spectrum in the fourth row with the spectrum shown in the second row, it is obvious that the peaks of interest are significantly increased and that no new peaks appear additonally.