全氟及α,α-二氯多氟烷基亚磺酸盐的反应

全氟烷基亚磺酸钠与溴水反应,得到全氟烷基磺酰溴(RfSO2Br),(但在乙腈,乙酸等有机溶剂中与溴反应,则生成溴代全氟烷.在碘化钾水溶液中,全氟烷基亚磺酸钠与碘反应,生成碘代全氟烷.α,α-二氯多币烷基亚磺酸钠在类似条件下与溴水反应,生成1-溴-1,1-二氯多氟烷,与碘在磺化钾水溶液中反应,生成1-碘-1,1-二氯多氟烷.1-溴-1,1-二氯多烷及1-碘-1,1-二氯多氟烷易对烯键加成,也可与连二亚硫酸钠在温和条件下发生亚磺化脱溴及脱碘反应.α,α-二氯二氟乙基亚磺酸钠在强酸中比较稳定,与强碱,氧化剂或还原剂发生反应,得到相应的产物.     

Non-destructive determination of trace amounts of iodine in biological samples by epithermal neutron activation and Compton suppression gamma-ray spectrometry

In order to investigate the ingestion of iodine by human body and to know its content in organs, instrumental epithermal neutron activation analysis was used in conjunction with Compton suppression gamma-ray spectrometry by measuring the ¹²⁸I short-lived nuclide. The interferences of ²⁴Na and ³⁸Cl induced from NaCl in a sample were reduced by factors of about 6 and 15 to 41 by employing the epithermal neutron activation and Compton suppression gamma-ray spectrometry, respectively. The present method can be used to determine iodine at levels higher than 11 ppb. It was applied to the determination of iodine of more than 35 ppb in various biological reference materials.     

Resonance activation analysis of iodine

Resonance neutron activation and gamma-ray spectrometry were used to determine traces of iodine in biological materials. The method developed is purely instrumental and fairly rapid. The major interfering activities of²⁴Na,³⁸Cl,³⁶Mn and⁸²Br were significantly reduced by irradiating the samples inside a shield of Cd, NaCl, MnBr₂ and MnO₂. Neutrons with energies close to the resonances of Na, Cl, Mn and Br were absorbed in the shield and did not activate the sample while neutrons with energies close to the resonances of iodine were not absorbed appreciably. Thus the activity of¹²⁸I was enhanced relative to the interfering activities. The 442 keV gamma of¹²⁸I (T=25 min) was measured using a high-resolution Ge(Li) detector and a multichannel analyzer. Sensitivity of 0.05 ppm was obtained.     

Neutron activation analysis of Californian and Japanese rice

The main motivation in studying different types of rice was to determine how processing of rice affects its mineral composition, and to compare how it affects rice dietary intake. Specifically the estimated difference in between the brown and white rice produced in Japan and California are studied. These various rice samples were analyzed using neutron activation analysis technique available at the Utah Nuclear Engineering Program (UNEP). Samples were prepared using novel technique developed at UNEP and submitted for short and long irradiation. The detected elements were As, Br, Cl, Cd, Mn, Na, K. The concentrations of Mn, K and Na are significantly higher in the brown then in the white rice, while As, Br and Cl have more homogeneous presence and therefore smaller difference in concentration. Elemental concentration was compared with The Institute of Medicine (IOM) in the United States values of recommended dietary allowance and Food and Drug Administration (FDA) limits for harmful elements. From these measurements, only the concentration of Mn in rice satisfies daily needs in the range set as defined by IOM. The concentrations of potentially harmful elements are lower than FDA limits.     

Ionization energies of hypervalent Li2F,Li2Cl and Na2Cl molecules obtained by surface ionization electron impact neutralization mass spectrometry

Ionization energies of hypervalent Li(2)F, Li(2)Cl and Na(2)Cl molecules detected by surface ionization electron impact neutralization mass spectrometry are reported. The ionization energies were 3.78 +/- 0.2 eV for Li(2)F, 4.93 +/- 0.2 eV for Li(2)Cl, and 4.21 +/- 0.2 eV for Na(2)Cl. The ionization energies (IE) agree with theoretical ionization energies calculated by ab initio methods, supporting the theoretical prediction that Li(2)F has a hyperlithiated configuration in which the odd electron delocalizes over the two lithiums and with photoionization measurement. The first ionization energy of Na(2)Cl was experimentally confirmed earlier and for Li(2)Cl as well.8 We have developed and used this new approach for the problem--in the present work ions were first formed by surface ionization, followed by electron attachment (neutralization).     

Quantification of the trans influence in hypervalent iodine complexes

The trans influence of various X ligands in hypervalent iodine(III) complexes of the type CF(3)[I(X)Cl] has been quantified using the trans I-Cl bond length (d(X)), the electron density ρ(r) at the (3, -1) bond critical point of the trans I-Cl bond, and topological features of the molecular electrostatic potential (MESP). The MESP minimum at the Cl lone pair region (V(min)) is a sensitive measure of the trans influence. The trans influence of X ligands in hypervalent iodine(V) complexes is smaller than that in iodine(III) complexes, while the relative ordering of this influence is the same in both complexes. In CF(3)[I(X)Y] complexes, the mutual trans influence due to the trans disposition of the X and Y ligands is quantified using the energy E(XY) of the isodesmic reaction CF(3)[I(X)Cl] + CF(3)[I(Y)Cl] → CF(3)[I(Cl)Cl] + CF(3)[I(X)Y]. E(XY) is predicted with good accuracy using the trans-influence parameters of X and Y, measured in terms of d(X), ρ(r), or V(min). The bond dissociation energy (E(d)) of X or Y in CF(3)[I(X)Y] is significantly influenced by the trans influence as well as the mutual trans influence. This is confirmed by deriving an empirical equation to predict E(d) using one of the trans-influence parameters (d(X), ρ(r), or V(min)) and the mutual trans-influence parameter E(XY) for a large number of complexes. The quantified values of both the trans influence and the mutual trans-influence parameters may find use in assessing the stability of hypervalent iodine compounds as well as in the design of new stable hypervalent complexes. Knowledge about the I-X bond dissociation energies will be useful for explaining the reactivity of hypervalent iodine complexes and the mechanism of their reactions.     

Determination of sodium and chlorine in pure water by neutron activation analysis

Neutron activation analysis was applied to determine sodium and chlorine in high purity water samples. After irradiation of the sample,³⁸Cl was purified from⁸²Br and other nuclides by carbon tetrachloride extraction and silver chloride precipitation, and²⁴Na was separated from other alkali elements and other nuclides by adsorption of²⁴Na on HAP. The activities of both elements were measured by conventional G.M. counter. The contamination of the elements from container walls during neutron irradiation and the interference with³⁸Ar(n, p)³⁸Cl reaction on argon dissolved in water were also examined. Water samples containing 3 ppb of chlorine could not be determined accurately, owing to the above mentioned interfering reaction.     

Sorption of cesium and strontium ions on hydrous titanium dioxide from chloride medium

Epiboron instrumental neutron activation analysis (EINAA) using flexible boron as thermal neutron filter, has been used to analyze several salt samples obtained from various markets in Ghana for iodine. The method involves the irradiation of samples in boron carbide-lined polyethylene vials at the outer irradiation site of the Ghana Research Reactor-1 (GHARR-1). The samples were then counted directly without any pre-treatment on a Canberra N-type HPGe detector. The qualitative and quantitative analyses were done using the 443 keV photopeak of ¹²⁸I. The precision and accuracy of the method have been evaluated and the detection limits of the various samples were calculated. The values of iodine determined in the iodized salt range between 10.0 and 210 ppm. For non-iodinated salts, iodine levels were below 500 ppb. The values obtained show great variations among the salt samples, sample collection time and from market to market. This results show that the method can be successfully applied in the determination of trace amount of iodine in salt samples without any chemical separation.     

SOD、MDA在自身免疫性甲状腺疾病患者血清中的变化及其与尿碘的关系研究

为了解重庆地区自身免疫性甲状腺疾病(AITD)患者体内SOD、MDA的变化情况及其与尿碘的关系,初步探讨碘在AITD发病中的作用机制,采用病例对照研究,检测并分析了各组人群外周血SOD、MDA及尿碘的含量.结果表明:(1)GD与HT组尿碘中位数高于对照组(P<0.000 1);(2)GD与HT患者血清中的MDA含量高于...     

Determination of 36Cl in biological shield concrete using pyrohydrolysis and liquid scintillation counting

A method for the determination of 36Cl in biological shield concrete of nuclear reactors was developed. Cl in the concrete sample was extracted quantitatively by pyrohydrolysis at 900 degrees C and recovered in Na2CO3 solution for subsequent measurement of 36Cl by liquid scintillation counting. WO3 was used as an accelerator in the pyrohydrolysis. The Cl extraction procedure was optimized by investigating experimental conditions with the use of ion chromatography and its recovery was evaluated by the analysis of the geochemical reference samples. The detection limit of 36Cl was 0.02 Bq g(-1) for a sample weight of 2 g. The relative standard deviation was 3-7% for the samples containing 0.5 Bq g(-1) levels of 36Cl. The method was applied to determine 36Cl in biological shield concrete of the Japan Power Demonstration Reactor.     

Determination of bromine, chlorine and iodine in environmental aqueous samples by epithermal neutron activation analysis and Compton suppression

Summary Halides, particularly Br^- and Cl^-, have been used as indicators of potential sources of Na⁺ and Cl^- in surface water and groundwater with limited success. Contamination of groundwater and surface water by Na⁺ and Cl^- is a common occurrence in growing urban areas and adversely affects municipal and private water supplies in Illinois and other states, as well as vegetation in environmentally sensitive areas. Neutron activation analysis (NAA) can be effectively used to determine these halogens, but often the elevated concentrations of sodium and chlorine in water samples can give rise to very high detection limits for bromine and iodine due to elevated backgrounds from the activation process. We present a detailed analytical scheme to determine Cl, Br and I in aqueous samples with widely varying Na and Cl concentrations using epithermal NAA in conjunction with Compton suppression.     

Shift of chemical equilibria and transformation laws in 12-salt six-component reciprocal systems in melt

Ten six-component 12-salt systems of various types were studied: Na,K,Ca,Ba‖F,SO₄,WO₄ (type 2ABD); Na,K,Ca‖F,Cl,SO₄,WO₄ (type AC2D); Na,K,Ca,Ba‖Cl,SO₄,WO₄ (type 4A); Na,K,Ca,Ba‖F,Cl,WO₄ (type AC2D); Li,Na,K‖Cl,Br,NO₃,SO₄ (type ABCC); Na,K,Ca,Ba‖F,Cl,SO₄ (type ABCC); K,Ca,Ba‖F,Cl,SO₄,WO₄ (type ABCC); Na,K,Ba‖F,Cl,SO₄,WO₄ (type 3AD); Na,Ca,Ba‖F,Cl,SO₄,WO₄ (type 3AB); and Na,Ca,Ba‖F,Cl,SO₄,MoO₄ (type 3BC). Laws governing the shift of exchange chemical equilibrium in these systems were determined for first time. Two groups of 12-salt systems were recognized. These groups differ in the number of the most stable salts, which have the highest indices in the matrix of vertex indices, and in the topology of their basal tetrahedra (the major elements of the singular star), which are either symmetrical or asymmetrical druses. The transformation of exchange reaction stages in going from nine-salt systems to a 12-salt system was determined. In this way, we revealed a correlation between the shift of exchange chemical equilibrium and the topology of the geometric model of a 12-salt reciprocal system, as well as with the thermo-chemical relations in this system and in the nine-salt five-component reciprocal subsystems. All models completely correlate with each other and with Kurnakov’s principle.     

A search for losses of chemical elements during freeze-drying of biological materials

Possible losses of seven chemical elements were investigated in biological tissues during freeze-drying in vacuum. Thyroid glands were taken during post-mortem examination of 23 people died of different diseases. Instrumental neutron activation analysis (INAA) was used to estimate contents of Br, Ca, Cl, I, K, Mg, and Na. The nuclear reator vertical channel with flux density of 1.2·10¹³n·cm^–2·s^–1 was used for neutron irradiation. The analysis was carried out using short-lived radionuclides induced in samples after neutron irradiation. Then thyroids were freeze-dried at below 0 °C in vaccum up to the constant mass (lyophilisation) and then homogenized. Samples of lyophilised and homogenized tissues were again studied by INAA. The lack of difference between the results of the analysis before and after lyophilisation is an evedence of no loss of Br, Ca, Cl, I, K, Mg and Na during freeze-drying of biotissues in vaccum.     

Neutron activation analysis of iodine in blood serum or other biological materials by substoichiometric precipitation of iodine as silver iodide

Several modifications are proposed of the established methods of iodine determination in serum. Prior to the actual analysis, the serum is lyophilized. This preliminary treatment permits the use of large samples. Through lyophilization human blood serum samples can easily be reduced to one-tenth of the original weight. Reduction is even more dramatic with materials from other than human origin. After irradiation the samples are subjected to chemical treatment in the presence of an iodine carrier and¹³¹I-labelled thyoxine. This procedure has been adopted for the determination of the iodine content and the chemical yield in one and the same radioactive measurement. The analysis technique itself consists of an open system Schöniger combustion. The open combustion allows the use of large samples; the gases evolved are absorbed upon their subsequent passage through potassium hydroxide and hydrochloric acid; the mineralization requires less than two minutes. After the addition of a substochiometric amount of silver nitrate, silver iodide is precipitated from an ammoniacal solution as a flat sample, which has been found ideally suited for high efficiency counting with a Ge(Li) detector. The spectrum gives evidence of an excellent decontamination from the³⁸Cl,⁸⁰Br and⁸²Br activities. The iodine content can be calculated from the ratio of the photopeak areas at 364.5 keV and 442.7 keV corresponding to¹³¹I and¹²⁸I, respectively. The chemical procedure requires a mere 15 min, and the recording of the γ-ray spectrum takes no longer than 30 min. The technique is not limited to serum only. It proved well suited for the analysis of many other types of biological material, e.g. human skin tissues.     

The determination of some trace elements in rainwater by neutron activation analysis

A routine method for the determination of 12 elements in small rain water samples is presented. Instrumental neutron activation analysis is applied for the determination of Mn, Na, Cl, V and Al. Bromine and iodine are isolated by isotope exchange between the irradiated water and a solution of Br₂ resp. I₂ in CCl₄. Extraction with APDC/MIBK is used for the separation of the shortlived isotopes of Co, V, Cr, Zn and In.     

Adsorption of water molecules on selected charged sodium-chloride clusters

The adsorption of water molecules (H(2)O) on sodium chloride cluster cations and anions was studied at 298 K over a mass range of 100-1200 amu using a custom-built laser desorption ionization reactor and mass spectrometer. Under the conditions used, the cations Na(3)Cl(2)(+) and Na(4)Cl(3)(+) bind up to three water molecules, whereas the larger cations, Na(5)Cl(4)(+) to Na(19)Cl(18)(+), formed hydrates with one or two only. The overall trend is a decrease in hydration with increasing cluster size, with an abrupt drop occurring at the closed-shell Na(14)Cl(13)(+). As compared to the cluster cations, the cluster anions showed almost no adsorption. Among smaller clusters, a weak adsorption of one water molecule was observed for the cluster anions Na(6)Cl(7)(-) and Na(7)Cl(8)(-). In the higher mass region, a substantial adsorption of one water molecule was observed for Na(14)Cl(15)(-). Density functional theory (DFT) computations were carried out for the adsorption of one molecule of H(2)O on the cations Na(n)Cl(n-1)(+), for n = 2-8, and the anions Na(n)Cl(n+1)(-), for n = 1-7. For each ion, the structure of the hydrate, the hydration energy, and the standard-state enthalpy, entropy, and Gibbs energy of hydration at 298 K were computed. In addition, it was useful to compute the distortion energy, defined as the electronic energy lost due to weakening of the Na-Cl bonds upon adsorption of H(2)O. The results show that strong adsorption of a H(2)O molecule occurs for the linear cations only at an end Na ion and for the nonlinear cations only at a corner Na ion bonded to two Cl ions. An unexpected result of the theoretical investigation for the anions is that certain low-energy isomers of Na(6)Cl(7)(-) and Na(7)Cl(8)(-) bind H(2)O strongly enough to produce the observed weak adsorption. The possible implications of these results for the initial hydration of extended NaCl surfaces are discussed.     

Radioanalytical studies of iodine behaviour in the environment

The behaviour of iodine in the environment is of interest both in relation to radioecology and human nutrition. Radiochemical techniques were used to evaluate various aspects of the behaviour of iodine in the environment. The natural iodine content of plant, water and soil samples collected from three sites was determined using preconcentration neutron activation analysis (PNAA). The effect of initial chemical speciation on the distribution of iodine between various soils, sediments and waters was evaluated using I-131 tracer. Iodide was found to adsorb more extensively than iodate, although for most of the solid/water systems examined, a substantial portion of the iodate was slowly reduced to iodide. Experiments involving gamma irradiation suggest that much of the sorption of iodide and reduction of iodate involved microbial processes. Distribution coefficients measured using I-131 were comparable with values based on the natural I-127 content.     

Neutron activation analysis of Ca, Cl, Mg, Na, and P content in human bone affected by osteomyelitis or osteogenic sarcoma

The Ca, Cl, Mg, Na, and P content and Ca/P, Ca/Mg, Ca/Na, Cl/Ca, and Cl/Na ratios in samples of intact cortical bone, inflamed bone and osteogenic sarcoma tissue were investigated by neutron activation analysis with high resolution spectrometry of short-lived radionuclides. In osteogenic sarcoma tissue the mass fractions of Cl and Na are higher and the mass fraction of Ca is lower than that of both normal and inflamed bone tissues. It was shown that the differences between the Cl/Ca ratio can be used as an additional test for differential diagnosis between normal or inflamed bone and osteogenic sarcoma.     

Trace element determinations in shale oil products by neutron activation

Neutron activation offers some important advantages for the determination of selected trace elements in shale oil products. This paper gives techniques and results of a study of crude shale oil and naphtha, heavy distillate, and wax products of shale oil. The elements determined were Al, As, Au, Br, Ce, Cl, Co, Cr, Fe, Hg, I, K, Mn. Mo, Na, S, Sb, Se, V, and Zn. Some elements (Mn, Na, As) tend to accumulate in heavier fractions, whereas chlorine and iodine are concentrated in the more volatile fractions. The volatility of sulphur compounds in the shale oil products appears to be essentially uniform, with some tendency toward accumulation in distillation residues. The tendency for the trace elements to accumulate in the waxes that precipitated from cooled heavy distillates was very low.