Towards speciation of organically bound tritium and deuterium: Quantification of non-exchangeable forms in carbohydrate molecules

Assimilation and transport of organic bound tritium in an irrigated pine forest

“…NE-OBT was the most common tritium species in the extracts of these most recent 20-yr core sections but the sum of the tritium fractions was typically 1.3 Bq g -1 less than the total tritium as determined by combustion. Our preliminary studies with tree core tissue concurred with the literature that period of 72 h 5,36 would be sufficient to isotopically-exchange H for tritium in E-OBT (unpublished SRNL data). But there was the potential for some loss of tritium despite efforts to contain the tritium vapor during the H-T exchange during this 72-h period.…”

“…47 Another issue that has been addressed in the recent literature is the need for more consistency in the quantification of NE-OBT and E-OBT amongst researchers 48 as well as related concerns over the inadvertent loss of NE-OBT when tritium is exchange with "dead water" to obtain E-OBT values. 5 Issues like these can certainly explain some of the variation that is observed in the literature and make comparisons between studies difficult.…”

“…Transfer of tritium upwards in a food chain generally results in the depletion of tritium in biological tissue 2,3,4 and with some conversion of HTO to organic bound tritium (OBT) forms. 5 The conversion of HTO to OBT through plant photosynthesis, respiration, and the active transport to make proteins, lipids, carbohydrates and many other necessary molecules for existence is thought to be a slow process. 6,7 But under specific circumstances, tritium can become accumulated as OBT by biota when it is released in the environment as persistent and "technologically enhanced" tritiated organic compounds, 8,9 when the organisms have access to a tritiated food source, 10 and when tritium becomes absorbed as a tritium-rich vapor onto plant tissue.…”

“…Several researchers have delineated exchangeable organically-bound tritium (E-OBT) from nonexchangeable organically-bound tritium (NE-OBT) in their reviews and studies with biota. 5,6,12,13,14,15 They have defined E-OBT as being tritium bound to either O or N whereas NE-OBT was defined as tritium bound to C but the terminology for defining OBT varies widely in the literature. These authors collectively classify tritiated water in tissues as "tissue free water tritium" (TFWT).…”

The effect of processing medium on the 2H/1H of carbon‐bound hydrogen in α‐cellulose extracted from higher plants

“…In some plant species where the microcrystalline component dominates the α-cellulose, the value of f can be as high as 87%. 29 According to Equation (1), the value of Δδ 2 H α-cel_C-H can be significantly magnified if a similarly high value of f is applied to the E. longifolia stem, making the measured δ 2 H value unreliable. Therefore, it is highly recommended that experiments should be designed to characterize the crystallinity of α-cellulose (in particular those samples extracted from newly explored species/organs) and to obtain a realistic value for f if reliable correction for the contribution of exchangeable H is to be made.…”