To order to examine experimentally the modified monostandard method implemented in the program MULTINAA, the FRM reactor in Garching (Germany) was calibrated and an INAA of a standard reference material NIST/SRMI1633b Coal Fly Ash was performed. The relative, thek0-and the modified monostandard standardizations are applied. This work shows that for all of the examined 1/-nuclides the modified monostandard method provides identical analytical results to those determined by thek0-method. For the non-1/ nuclides177Lu and152Eu the monostandard results are correct. Compared with the certified values of the analysed SRM1633b sample and also with the results of the relative method, it can be concluded that the modified monostandard method performed at our experimental conditions gives analytical results with accuracy better than 5%.
A modified NiS fire-assay neutron activation method is developed for the determination of all platinum-group elements (PGEs) in mantle-derived xenoliths. This method is characterized by sub-ppb detection limits, <0.1~0.002 ppb procedural blanks and 7~15% analytical precision for PGEs. Analyses of PGE standard rocks indicate that this modified NiS fire-assay neutron activation method is as reliable as the method previously proposed for a large scale of samples. The capability of the method for the measurement of PGEs in the upper mantle is also illustrated by some exciting results obtained from mantle-derived xenoliths of Eastern China.
A compute program MULTINAA was developed to facilitate the evaluation of NAA data. It is written for the VAX/VMS syste and opeates in the Canberra/ND Genie spectroscopy software environment. MULTIINAA can be appliede to relative,k0-, monostandard (modified) and absolute methods, including the fast neutron threshold reaction. For each calculation, the available standardizations can be used individually or mixed. In all the standardization modes MULTINAA fetches the data directly from the -ray spectra and libraries, thus reducing the manual work to a minimum. MULTINAA is flexibkle to meet various situations in NAA practical work. The required neutron flux parameters all the non-relative methods are supplied by an accompanying program MULTIFLUX.
Triclocarban (TCC) and triclosan (TCS) are used in a wide range of household and personal care products and have been the most frequently detected organic pollutants in both wastewater and surface water. This paper presented a rapid analytical method for simultaneous determination of TCC and TCS in wastewater. The method involves the extraction and cleanup of the target compounds by using silicon dioxide/polystyrene composite microspheres solid-phase extraction and detection with ultra-high-pressure liquid chromatography. Under the optimized conditions, the limits of detection were 0.028 μg/L and 0.040 μg/L for TCC and TCS, respectively. Under the concentrations of the spiking level ranging from 0.100 μg/L to 2.000 μg/L, the spiked recoveries of TCC and TCS in wastewater samples achieved in the range of 89.5–102.8% with RSD below 6.3% for TCC and 95.5–103.6% with RSD below 6.9% for TCS. This method was successfully used in monitoring the water samples from three traditional wastewater treatment plants.
By using 188Re as a radiotracer, the extraction behavior of Re(VII) by a tertiary amine extractant N-235 from HCl and the back-extraction behavior of Re(VII) by HNO3 and ammonia were studied. A chemical separation procedure, which combined the acid alumina column and solvent extraction was established. The procedure was rapid and efficient for the separation of 186Re from 186W irradiated by 16 MeV deuterons. No-carrier-added 186ReO4– saline solution with high specific volume activity was obtained. The overall recovery yield of 186Re was about 85%.
An isothermal method was applied to measure the thermal
decomposition of reactive solids in a sensitive heat flux reaction calorimeter,
C80. This technique experimentally clarified the decomposition mechanisms
of unstable substances based on the shapes of the heat flow curves, from which
autocatalysis, first-order reaction or pseudo-autocatalytic reaction could
be recognized. Kinetic parameters were derived from the measured data.
Contamination and adsorption of trace elements during storage of natural water samples in polyethylene containers have been studied. Variations of concentrations of 29 elements in pH=1.5 natural water samples stored in polyethylene bottles for 15 and 30 days respectively were determined by the method of freeze-drying preconcentration and NAA. The percentage adsorption loss of radioactive indicators60Co,124Sb,65Zn,75Se,134Cs and46Sc in the pH=1.5–8.0 reservoir water, tap water and distilled water stored for 1–2 months were also determined. The optimized storage condition for natural water is obtained.
Authors:X. Wang, X. Yin, X. Zhang, Z. Li, J. Tian, M. Wu, and X. Sheng
A radioactive multitracer solution obtained from the nuclear reaction of selenium with 25 MeV/nucleon40Ar ions was applied to the investigation of the trace elements behavior in feces and urine of mouse. The excretion rates of
23 elements, Na, K, Rb, Mg, Ca, Sr, Ga, As, Sc, V, Cr, Mn, Co, Fe, Zn, Y, Zr, Mo, Nb, Tc, Ru, Ag and In were simultaneously
detected under strictly identical experimental conditions, in order to clarify the excretion behavior of the elements in mice.
Fecal and urinary excretion rates of the elements in mice reached the highest value separately at 48 and 24 hours. The total
excretion of Mo, Tc and Co within 96 hours were all larger, more than 60%. Accumulative excretion rates of Ca, Nb, Mg, Sr,
V, Sc, Na, Cr, Fe, Ag, Mn and Zr were 60-30%. The total rates of Ru, K, As, Zn, Rb, Y, Ga and In were less than 30%, and low
excretion. The main excretion pathway of Mo, Co, Mg, Fe and Ag was through urine, and Na, K, As and Rb were eliminated from
the body also in urine. But fecal excretion of Tc, Nb, Sr, Y, Ru, and In were larger than urinary excretion, and Ca, Sc, Mn,
Zr, Zn were eliminated from the body in feces.
Laburnine's dissolution behaviors in glucose and saline solution were studied by a micro-calorimetry method. The measured integral and differential heats of solution were utilized to build equations of the solute and the heat, so that dissolution thermodynamic equations and half-time periods, ΔsolHm, ΔsolGm, and ΔsolSm were obtained. The results show that this study does not only provide a simple method for the determination of the half-life period for a drug but also offer a theoretical reference for the clinical application of laburnine.
In this article, the enthalpy of dissolution for oxymatrine in 0.15 M citric acid solution is measured using a RD496-2000 Calvet Microcalorimeter at 36.5 °C under atmospheric pressure. The differential enthalpy (ΔdifHm) and molar enthalpy (ΔsolHm) were determined for oxymatrine dissolution in 0.15 M citric acid solution. On the basis of these experimental data and calculated results, the kinetic equation, half-life, ΔsolHm, ΔsolGm, and ΔsolSm of the dissolution process were also obtained.