Schoeller D A, Colligan A S, Shriver T, Avak H, Bartok-Olson C
Nutritional Sciences, University of Wisconsin, Madison, Wisconsin 53706, USA.
J Mass Spectrom. 2000 Sep;35(9):1128-32. doi: 10.1002/1096-9888(200009)35:9<1128::AID-JMS41>3.0.CO;2-Y.
The doubly labeled water method is commonly used to measure total energy expenditure in free-living subjects. The method, however, requires accurate and precise deuterium abundance determinations, which can be laborious. The aim of this study was to evaluate a fully automated, high-throughput, chromium reduction technique for the measurement of deuterium abundances in physiological fluids. The chromium technique was compared with an off-line zinc bomb reduction technique and also subjected to test-retest analysis. Analysis of international water standards demonstrated that the chromium technique was accurate and had a within-day precision of <1 per thousand. Addition of organic matter to water samples demonstrated that the technique was sensitive to interference at levels between 2 and 5 g l(-1). Physiological samples could be analyzed without this interference, plasma by 10000 Da exclusion filtration, saliva by sedimentation and urine by decolorizing with carbon black. Chromium reduction of urine specimens from doubly labeled water studies indicated no bias relative to zinc reduction with a mean difference in calculated energy expenditure of -0.2 +/- 3.9%. Blinded reanalysis of urine specimens from a second doubly labeled water study demonstrated a test-retest coefficient of variation of 4%. The chromium reduction method was found to be a rapid, accurate and precise method for the analysis of urine specimens from doubly labeled water.
双标记水法常用于测量自由生活个体的总能量消耗。然而，该方法需要准确且精确地测定氘丰度，这可能很费力。本研究的目的是评估一种用于测量生理流体中氘丰度的全自动、高通量铬还原技术。将铬技术与离线锌弹还原技术进行比较，并进行重测分析。对国际水标准的分析表明，铬技术准确，日内精密度<1‰。向水样中添加有机物表明，该技术对2至5 g l(-1)水平的干扰敏感。生理样本可在无此干扰的情况下进行分析，血浆通过10000 Da排阻过滤，唾液通过沉淀，尿液通过用炭黑脱色。来自双标记水研究的尿液样本的铬还原表明，与锌还原相比无偏差，计算能量消耗的平均差异为-0.2±3.9%。对第二项双标记水研究的尿液样本进行盲法重新分析，显示重测变异系数为4%。发现铬还原法是一种快速、准确且精确的方法，用于分析来自双标记水的尿液样本。
