ac9b04388_si_001.pdf (108.14 kB)
Exploring Triple-Isotopic Signatures of Water in Human Exhaled Breath, Gastric Fluid, and Drinking Water Using Integrated Cavity Output Spectroscopy
journal contribution
posted on 2020-04-01, 11:43 authored by Mithun Pal, Sayoni Bhattacharya, Abhijit Maity, Sujit Chaudhuri, Manik PradhanWater,
the major body fluid in humans, has four main naturally
occurring isotopologues, H216O, H217O, H218O, and H2H16O (i.e., HD16O) with different masses. The underlying
mechanisms of the isotope-specific water-metabolism in the human gastrointestinal
(GI) tract and respiratory system are largely unknown and remained
illusive for several decades. Here, a new strategy has been demonstrated
that provides direct quantitative experimental evidence of triple-isotopic
signatures of water-metabolism in the human body in response to the
individual’s water intake habit. The distribution of water
isotopes has been monitored in drinking water (DW; δD = −36.59
± 10.64‰ (SD), δ18O = −5.41 ±
1.47‰ (SD), and δ17O = −2.92 ±
0.79‰ (SD)), GI fluid (GF; δD = −35.91 ±
7.30‰ (SD), δ18O = −3.98 ± 1.29‰
(SD), and δ17O = −2.37 ± 0.57‰
(SD)), and human exhaled breath (EB; δD = −119.63 ±
7.27‰ (SD), δ18O = −13.69 ± 1.23‰
(SD), and δ17O = −8.77 ± 0.98‰
(SD)) using a laser-based off-axis integrated cavity output spectroscopy
(OA-ICOS) technique. This study explored a new analytical method to
disentangle the competing effects of isotopic fractionations of water
during respiration in humans. In addition, our findings revealed that
deuterium-enriched exhaled semiheavy water, i.e., HD16O
is a new marker of the noninvasive assessment of the ulcer-causing H. pylori gastric pathogen. We also clearly showed that
the water-metabolism-derived triple-isotopic compositions due to impaired
water absorption in the GI tract can be used as unique tracers to
track the onset of various GI dysfunctions. These findings are thus
bringing a new analytical methodology to better understand the isotope-selective
water-metabolism that will have enormous applications for clinical
testing purposes.