Evaluation of Water Removal and Memory Effect in 13CO2 Breath Tests by Isotope Ratio Mass Spectrometry |
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| Authors: | W. Meier-augenstein A. Hess G. F. Hoffmann D. Rating |
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| Affiliation: | 1. Universit?tskinderklinik Heidelberg, Abt. für P?diatrische Neurologie , Stabil-Isotopen- und GC/MS-Labor, Heidelberg, Germany;2. Universit?tskinderklinik Heidelberg, Sektion P?diatrische Stoffwechselkrankheiten , Heidelberg, Germany |
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| Abstract: | The usefulness of different ways of water removal in off-line sample preparation of human breath samples for 13CO2 breath tests was examined and compared. Cryogenic water trapping and water removal with common desiccants like silicagel blue, Mg(ClO4)2, and molecular sieves were checked for reliability and reproducibility. With silicagel blue and Mg(ClO4)2 memory effects for 13C content were observed. The use of molecular sieve 4 Å and 5 Å led to tremendous carbon isotope fractionation. Molecular sieve 3 Å was found to be an excellent alternative to the established use of Mg(ClO4)2 and of cryogenic water trapping. |
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| Keywords: | 13CO2 breath test isotopic fractionation memory effect off-line techniques water removal |
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