Tritium analysis

Tritium Analysis. Figure 13 shows the laboratory equipment used for sample preparation and counter filling. The bomb converter is designed to prepare methane for both carbon-14 and tritium analysis. The chemical reactions are ... 

After extensive effort to perfect the method, it was found that environmental water and memory effects occurred in the bomb reactors. Since the reactor had to be opened to change the zinc and add the water sample, environmental water was adsorbed in the reactor. Neither the environmental contamination nor memory effects could be removed completely by evacuating the reactor within a reasonable time. This technique is promising, but further work must be done to eliminate these problems before it can be used routinely for low level tritium analysis. 

Table IV. Tritium Analysis of Nevada Well and Ground Water...

A water sample is brought into a laboratory for tritium analysis. Three separate fractions of 250 mL each are removed from the 1-gallon container, distilled separately. A 10 mL portion is taken for counting as was done in this experiment. The results were 130 Bq/L, 52 Bq/L and 110 Bq/L. Calculate the average and standard deviation of the mean. What might contribute to the spread in the results Explain. 

The recommended approaches for storing samples intended for tritium analysis are... 

M.P. Neary, J.D. Spaulding, J.E. Noakes, R.A. Culp (1997) Tritium analysis of burn-derived water from natural and petroleum-derived products. J. Agric. Food Chem. 45. 2153-2157... 

Reduction of Unsaturated Steroids.—Reduction with di-imide [provided by hydrazine hydrate and copper(ii) acetate in methanol] provides a novel and stereospecific conversion of steroidal 4-en-3)5-ols into 5a-dihydro-compounds. By contrast, catalytic hydrogenation is non-stereospecific and is often accompanied by partial hydrogenolysis, so the new method offers considerable promise. Catalytic reduction of 3jS-hydroxyandrost-4-en-17-one with tritium and a Pt catalyst gave 3)5-hydroxy-5a-androstan-17-one with the tritium distribution 4a, 37% 5a, 43% and 6a, 20%. The 5jS-isomer was also formed, with tritium at 4, 29 % 5, 54 % 6, 4.7 %, and 6a, 13 %. Tritium analysis was achieved by a combination of equilibration with base, bromination-dehydrobromination, and dehydrogenation. The appearance of tritium at C-6 indicates olefinic bond migration in contact with the catalyst. ... 

All charges for analysis of samples are based on current charges of Oregon State University s in-house service analysis groups. The tritium analysis charge includes cost of preconcentration. 

Although chemical reactions of radionuclides are assumed, for practical purposes, to be identical to those of their natural stable isotope mixtures, minor differences in equilibrium distribution exists, notably in the case of tritium relative to stable hydrogen, but also to a small extent for others, such as C relative to stable carbon. During water distillation to purify it for tritium analysis, the tritium concentration of the residue is enriched by about 10% relative to the vapor. Only when all of the water is distilled will the specific activity of tritium (and the concentration in water, in units of Bq be the same in the distillate and the sample (Baumgartner and Kim 1990). Moreover, because of such differences in equilibrium constants, the tritium concentration can be enriched approximately 10-fold by electrolysis of a water sample from which the produced hydrogen gas escapes into the air (NCRP 1976a). 

The field deployable tritium analysis system (FDTAS) (Hofstetter et al., 1999) samples water, purifies the sample, and performs Compton-suppressed LS counting to achieve laboratory-quality analyses. The system described by Fig. 15.10 has remote reporting and control capability. 

Moghissi, A. A., Bretthauer, E. W., and Compton, E. H. 1973. Separation of water from biological and environmental samples for tritium analysis. Anal Chem 45, 1565-1566. Momyer, F., Jr. 1960. The Radiochemistry of the Rare Gases. National Academy of... 

In order to define the potential Improvement to the health and safety of the public, the actual LLDs calculated under the current RETS, proposed RETS with the assumed relative systematic uncertainty bounds and the proposed RETS with calculated relative systematic uncertainty bounds have been determined for two of the robust techniques under consideration tritium analysis and low level 1-131 analysis. The third technique, gamma spectroscopy, has been shown to be robust with respect to the LLD requirements... 

The tritium analysis case was further evaluated in accordance with Method IV by preparing a tap mter saiq>le (from well water) with a tritium standard so the resulting concentration was equal to the required LLD (lE-5 iCi/mL). The sanq>le has been analyzed a total of twenty-six times under the standard protocol with the following results s 1.06jK0.06B-5 pCi/mL. Bach sample... 

Three methods of tritium analyses were reviewed by the Yankee Atomic Environmental Laboratory (YAEL) prior to selection of a preferred method to use in their tritium analysis program. The first method considered entailed a sample preparation procedure encompassing distillation of the aqueous samples at atmospheric pressure followed by LS counting using an aqueous cocktail. The second procedure reviewed entailed elec-... 

Several techniques were described to study hydrogen-deuterium exchange in solution. The Linderstrom-Lang freeze drying method involved isolation of either isotopically enriched solvent water or protein. Methods substituting tritium for deuterium, thereby increasing the sensitivity, were developed. In this case, scintillation techniques were used for tritium analysis. Easier separation methods such as gel filtration or dialysis replace the freeze drying one. 

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