Accuracy of delta O-18 isotope ratio measurements on the same sample by continuous-flow isotope-ratio mass spectrometry

摘要

RATIONALE: The doubly labeled water method is considered the reference method to measure energy expenditure. Conventional mass spectrometry requires a separate aliquot of the same sample to be prepared and analyzed separately. With continuous-flow isotope-ratio mass spectrometry, the same sample could be analyzed sequentially for both H-2 and O-18 content and thus minimize sample requirement, reduce analytical cost, and avoid memory effect.