Isotopic fractionation of fentanyl (FT) and its deuterated analogues by gas chromatography using capillary columns (CBP1 and CBP5) has been investigated. Seven kinds of analogues were labeled with 5 to 19 deuterium atoms at the anilino, propionyl and/or phenylethyl group of FT. The retention times of deuterated FT in CBP1 and CBP5 columns are inversely proportional to the number of labeled deuterium atoms in the molecule. The difference in free energy changes (ΔΔG) had a linear relationship with the number of labeled deuterium atoms, except for labeling at anilino and phenylethyl group. The contribution of a deuterium atom to the ΔΔG value was estimated to be 1.13 cal/mol in CBP1 and 1.40 cal/mol in CBP5, respectively. While, its contribution in the propiony group was 2.84 cal/mol in CBP1 and 2.48 cal/mol in CBP5, respectively. An important factor in separation by GC may differences in interactions between the stationary phase of the column with the three dimensional protrusive moiety in the molecule.
Liquid scintillation counters are widely used for the assay of β-ray emitting radioisotopes. In Japan it is mandatory for liquid scintillation cocktail waste containing 5 nuclides (3H, 14C, 32P, 35S, 45Ca) to be incinerated by a specially designed incineration system. We examined the performance of incineration systems and beheavior of radioisotopes during incineration from the viewpoints of safe handling of radioisotopes and environmental protection. Size distribution of radioactive particles in the exhaust air was studied. 3H and14C were not observed because they produce gaseous chemical compounds during incineration. 32P, 35S and45Ca particles were less than 1μm, between 0.1 and 1μm (U-shape distribution with minimum at 0.3-0.6 μm), and between 0.1 and 3μm (with maximum at 1 μm), respectively. Translocation percentages of3H, 14C, 32P, 35S, and 45Ca to the exhaust air and cooled washing water (exhaust water) were about 2.2, 94, 27, 5.6, 33 and 96, 1.3, 35, 76, 34%. pH values of the cooled washing water were about 5.5 and 7 under the normal incineration conditions and at the end of incineration, respectively. Chemical oxygen demand (COD) and insoluble substance concentrations in the exhaust water after incineration were less than 3 ppm and less than 5 mg/L, respectively. Trapping efficiency of the filter unit constructed with prefilters and HEPA filters for32P, 35S and45Ca particles were 99.95±0.02, 99.62±0.27, and 99.97±0.01%, respectively.
A prolonged irradiation facility to study late effects on mice by continuous γ-ray irradiation at low-dose rates was established at the Institute for Environmental Sciences (IES), Aomori prefecture, Japan. Before starting studies of late effects, the absorbed doses to mice were estimated in detail. Three137Cs γ-sources were individually used to expose mice in three irradiation rooms. The cages for mice were arranged so that the mean absorbed doses in the abdomen of a mouse would reach 8000, 400, 20mGy by exposures for about 400 days in respective rooms. The positions of the cages on the shelves of racks were presumed by using two air-ionization chambers whose ionization volume were about 12 and 1200 ml, respectively. Furthermore, by inserting TLD phosphors into the abdomens of mice, the absorbed doses were directly obtained under the actual exposure conditions. The absorbed dose distributions in air at the source level above the floor never showed an inverse-square law behavior with the distance from the source, and also never showed geometric symmetry in every irradiation room. Except for errors concerning the positions of the racks and cages, the uncertainties in the exposure doses were estimated to be about ±12% for a 8000 mGy group, 17% for a 400 mGy group and 35% for a 20 mGy group.
Floating radioluminography using an imaging plate can be sufficiently applied to the monitoring of the surface contamination on rough surface materials at a radioisotope facility. This technique is superior to the smear method which has been used to estimate the contamination of low energy β-ray emitters, because the fixed contamination and the contamination on the coarse surface materials have been difficult to be wiped out on a smear paper. The radiation detection efficiency of the imaging plate is as high as the liquid scintillation technique, when the plate is exposed with the sample in a vacuum chamber. In this study, the technique has been tested to the surface monitoring of a liquid-waste concrete cistern, and the sort of contaminant radioisotope was estimated by inserting a plastic film or an aluminum plate between the imaging plate and the sample.