Application of gas chromatography–tandem mass spectrometry (GC/MS/MS) for the analysis of deuterium enrichment of water |
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Authors: | Dillon K Walker John J Thaden Nicolaas E P Deutz |
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Institution: | Center for Translational Research in Aging and Longevity, Department of Health & Kinesiology, Texas A&M University, College Station, TX, USA |
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Abstract: | Incorporation of deuterium from deuterium oxide (2H2O) into biological components is a commonly used approach in metabolic studies. Determining the dilution of deuterium in the body water (BW) pool can be used to estimate body composition. We describe three sensitive GC/MS/MS methods to measure water enrichment in BW. Samples were reacted with NaOH and U‐13C3‐acetone in an autosampler vial to promote deuterium exchange with U‐13C3‐acetone hydrogens. Headspace injections were made of U‐13C3‐acetone‐saturated air onto a 30‐m DB‐1MS column in electron impact‐mode. Subjects ingested 30 ml 2H2O, and plasma samples were collected. BW was determined by standard equation. Dual‐energy X‐ray absorptiometry scans were performed to calculate body mass, body volume and bone mineral content. A four‐compartmental model was used to estimate body composition (fat and fat free mass). Full‐scan experiments generated an m/z 45 peak and to a lesser extent an m/z 61 peak. Product fragment ions further monitored included 45 and 46 using selected ion monitoring (Method1), the 61 > 45 and 62 > 46 transition using multiple reaction monitoring (MRM; Method2) and the neutral loss, 62 > 45, transition (Method3). MRM methods were optimized for collision energy (CE) and collision‐induced dissociation (CID) argon gas pressure with 6 eV CE and 1.5 mTorr CID gas being optimal. Method2 was used for final determination of 2H2O enrichment of subjects because of lower natural background. We have developed a sensitive method to determine 2H2O enrichment in BW to enable measurement of FM and FFM. Copyright © 2015 John Wiley & Sons, Ltd. |
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Keywords: | acetone body composition deuterium gas chromatography tandem mass spectrometry |
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