A rapid adsorption method has been developed to determine the60Co content in sea water samples. The60Co activity is concentrated by filtering the water sample through an adsorption column of steel work. A 60-liter sample can be processed in 1 h with 95% adsorption efficiency.
Authors:S. Yeh, C. Lin, C. Tsai, H. Yang, and C. Ke
An attempt was made to establish a reliable method using chemical neutron activation analysis for surveillance of pollutants in waste waters released by plants manufacturing various kinds of products. Since preconcentration process played important role in the entire course of the analysis work, special precaution was taken to re-confirm that the recovery efficiencies for pollutant ions were satisfactory during the preconcentration. It was also re-examined that the Langmuir's adsorption isotherm pattern well obeyed by all ions under investigation. In recent years, significant amounts of rare earth compounds and other raw materials containing representative elements have been imported and consumed to meet the demand due to the rapid progress in new manufacturing technology. Samples were collected from ten various production lines in plants and potential pollutants were determined using the Tsing Hua Open-pool Reactor. It would be noteworthy that the specimens obtained by this preconcentration process also would be usable for Induced Coupled Plasma-Mass Spectrometry analysis for supplementary and/or comparison purposes.
Authors:S. Lin, C. Chiang, C. Huang, C. Tseng, and M. Yang
Five kinds of urinary stones from 42 patients have been determined for a total of 19 elements by instrumental neutron activation analysis. Of these elements, Ca, Mg, Sr, Na, and Cl are found to be present in the core of all kinds of stones. The differences in elemental composition among the different kinds of stones as well as across the layers of stone are statistically evaluated.
A method combining prior collection of gaseous products with subsequent neutron activation analysis has been developed for simultaneous determination of traces of arsenic, mercury, antimony and selenium in biological materials. The generation of hydrides of arsenic, antimony and selenium and cold vapor of mercury in the vapor generaion and collection system was investigated by the use of radiotracers of the respective elements. The result indicates that selenium and mercury can be completely evaporated from the digested sample solution in 5M HCl with the addition of 5% sodium tetrahydroborate solution, while additional reduction proces by potassium iodide and ascorbic acid is needed for complete evaporation of arsenic and antimony. The gaseous products were collected in a quartz tube for neutron irradiation. The detection limits of these elements were fount to be in the range of 10–7 to 10–8 g under the present experimental conditions. The reliability was checked with NBS standard reference materials.
Method for the isolation and radioactive cobalt /including58Co and60Co/ from a large volume of seawater and concentration in a small volume of chloroform as tris/pyrrolidine dithiocarbamato/cobalt/III/, Co/PDC/3, is described. The seawater was extracted first with Bi/PDC/3 in chloroform for removing parts of foreign metals like Hg, Ag, etc., and then added with ammonium pyrrolidindithiocarbamate, APDC, to complex with Co and possibly other ions and extracted into the organic phase. The final separation of Co from foreign ions in the organic phase was achieved by stripping with a Bi/III/ solution. The overall recovery of radiocobalt activity was found to be about 96%. The established method can be applicable for rapid and reliable determination of radiocobalt in seawater and other aqueous systems for environmental contamination.
The conductivities of binary mixtures of glycerine and water were measured at 20C by means of a transient method. The equation
describing the correlation between concentration and thermal conductivity was determined. The equation can be used for determining
concentrations in mixtures. The results show that (1) the error in the determination of the molar concentration of water in
mixtures is less than 1%, (2) the time of measurement is 1 s, (3) this method can be used for on-line analysis in production
A preconcentration method of 13 rare earth elements (REES) was studied for neutron activation ananlysis (NAA). Hydrated magnesium oxide was used as the preconcentration agent to absorb the REES ions from aqueous solution onto the solid magnesium oxide, which was separated and analyzed. It was observed that the Langmuir equation for isothermal adsorption was well obeyed by the REES under the condition studied. The efficiency of the preconcentration process using hydrated magnesium oxide was critically examined for each of REE and for mixture of REES by preparing a known volume of solution containing known amount of trace REES. NAA was used to analyze REES recovered by the preconcentration process. It was found that the REES recoveries were satisfactory and the preconcentration process is reliable. There are several resort resort areas in Taiwan where local people are enjoying its hot spring water. It is generally believed that the hot spring water spa would bring about some sorts of therapeutic functions. The preconcentration method developed above, was applied to analyze the trace amounts of REES in hot spring wate in Taiwan.
The analysis of tin in biological materials is rarely reported. In this study, instrumental neutron activation analysis was used to determine the tin together with some other trace elements in various organs of rats treated with trialkyltin-methacrylic copolymer. No appreciable accumulation of tin and variation of distribution of trace elements (Cr, Fe, Zn and Co) in various organs are found. The pathological changes in the liver sections cannot be observed either. This therefore indicates that the toxicity of trialkyltin-methacrylic copolymer is low, if any.
In order to assure the public health, simple and relibable analytical methods must be established for effective surveillance of polluted surface water. Since the pollutants in surface water are usually found at ultratrace levels, preconcentration is generally required to ensure the quality of the analytical results. An analytical procedure consisting of preconcentration using hydrous magnesium oxide followed by neutron activation analysis has been proposed and applied to the determinations of trace elements in surface water.
Authors:X. Cao, Z. Wang, X. Yang, Y. Liu, and C. Wang
The kinetics of protein thermal transition is of a significant interest from the standpoint of medical treatment. The effect
of sucrose (0–15 mass%) on bovine serum albumin denatured aggregation kinetics at high concentration was studied by the iso-conversional
method and the master plots method using differential scanning calorimetry. The observed aggregation was irreversible and
conformed to the simple order reaction. The denaturation temperature (Tm), the kinetic triplets all increased as the sucrose concentration increased, which indicated the remarkable stabilization
effect of sucrose. The study purpose is to provide new opportunities in exploring aggregation kinetics mechanisms in the presence