Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5136588 | Journal of Chromatography B | 2017 | 6 Pages |
â¢HMB-Pentafluorobenzyl bromide derivative increases sensitive in GC/MS/MS.â¢Tandem mass spectrometer improves HMB measurement sensitivity.â¢HMB turnover in humans is 0.66 umol/kg ffm/h.
Our objective was to develop a quick and simplified method for the determination of β-Hydroxy-β-methylbutyrate (HMB) and É-ketoisocaproic acid (KIC) concentrations and enrichments by GC/MS/MS to determine the turnover rate of HMB in humans.In experiment 1, we provided a pulse of L-[5,5,5-2H3]leucine to younger adults in the postabsorptive state then collected blood samples over a 4 h time period. In experiment 2, we provided a pulse of [3,4,methyl-13C3]HMB to older adults in the postabsorptive state then collected blood samples over a 3 h time period. Plasma concentrations of KIC and HMB and MPE of KIC and HMB were determined by GC/MS/MS. Plasma enrichment of leucine was determined by LC/MS/MS.To determine plasma enrichment of [5,5,5-2H3]HMB and [3,4,methyl-13C3]HMB, samples were derivatized using pentafluorobenzyl bromide and analyzed using chemical ionization mode. The final methods used included multiple reaction monitoring of transitions 117.3 > 59.3 for M + 0 and 120.3 > 59.3 for M + 3. In experiment 1, peak MPE of Leu peaked at 9.76% generating a peak MPE of KIC at 2.67% and a peak HMB MPE of 0.3%. In experiment 2, the rate of appearance for HMB wasâ 0.66 μmol/kg ffm/h. We calculated that production of HMB in humans accounts for 0.66% of total leucine turnover.