Proton-decoupled 2H-NMR spectra of MAG samples were obtained with a Bruker Avance III HD 500 spectrometer using a 2H-selective 5 mm probe incorporating a 19F-lock channel. Samples were resuspended in 0.5 ml 90% acetonitrile/10% 2H-depleted water to which 50 μl of hexafluorobenzene were added. 2H-NMR spectra were obtained with a 90° pulse angle, 1.6 s of acquisition time and a 0.1 s interpulse delay. The number of fee-induction decays (f.i.d.) collected ranged from 2,000 to 10,000. Positional 2H-enrichments were determined using the MAG methyl signals as an intramolecular standard19 (link). To quantify plasma body water 2H-enrichments, triplicate 10 µl samples of plasma were analyzed by 2H NMR as previously described21 (link) but with 50 μl of hexafluorobenzene added to the NMR sample. Proton-decoupled 13C NMR spectra were obtained with a Varian VNMRS 600 MHz NMR (Agilent) spectrometer equipped with a 3-mm broadband probe. 13C NMR spectra were acquired at 25 °C using a 60° pulse, 30.5 kHz spectral width and 4.1 s of recycling time (4.0 s of acquisition time and 0.1 s pulse delay). The number of acquisitions ranged from 2,000 to 18,000. The summed f.i.d. was processed with 0.2 Hz line-broadening and zero-filled to 512 K before Fourier transform.
13C- and 2H-NMR spectra were analyzed with ACD/NMR Processor Academic Edition software (ACD/Labs, Advanced Chemistry Development, Inc.).
13C- and 2H-NMR spectra were analyzed with ACD/NMR Processor Academic Edition software (ACD/Labs, Advanced Chemistry Development, Inc.).