DETERMINATION OF TOTAL BODY WATER IN HUMANS BY DEUTERIUM NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY

Authors: Kehayias, Joseph; MURALI, NAGARAJAN - FLORIDA STATE UNIV; DUPONT, JACQUELYN - FLORIDA STATE UNIV

Submitted to: National High Magnetic Field Laboratory Technical Report
Publication Type: Other
Publication Acceptance Date: 1/1/1999
Publication Date: N/A
Citation: Kehayias, J.J., Murali, N., Dupont, J. 1999. Determination of total body water in humans by deuterium nuclear magnetic resonance spectroscopy. National High Magnetic Field Laboratory Technical Report #34.

Interpretive Summary:

Technical Abstract: Measuring total body water in the field can become an important tool for assessing nutritional status, testing the efficacy of pharmaceutical intervention, and managing obesity. The purpose of this project was to evaluate the capability of deuterium NMR analysis of blood serum and define the parameters of a dedicated portable NMR deuterium analyzer for field use. We used the 720 MHz NMR spectrometer at the National High Magnetic Field Laboratory in Tallahassee, FL. The spectrometer was used with its standard triple-resonance probe designed for C-13, N-15 and H-1, modified so that the deuterium signal was no longer used for locking, but as an observed channel (110.6 Mhz). Liquid samples (600 microl each) were measured at room temperature in 5mm diameter glass NMR sample holders. Deuteriated butanol (tetr-butanol-d9) was used in the samples as internal standard. Both resonances for deuterium in water and butanol appeared fully resolved 3.8 ppm apart. The reproducibility (one CV) of the area under the deuterium peak was better than 0.13% for high concentration samples (>0.1%). However, the reproducibility for the internal standard was found to be 4.1% between samples. Similarly, low concentration D2O solutions had reproducibility of 5%, most of which was attributed to the technique used for the area integration. In conclusion, we demonstrated that high field NMR spectroscopy has the sensitivity to measure natural concentrations of D2O in water, blood and urine, and the chemical-shift resolution required for the use of deuteriated butanol as internal standard. We found, however, that the precision of the instruments is only marginal when used with the manufacturer-supplied peak integration software, especially at the pre-dose low D2O concentrations.