Yuzuru Kusaka

RADIOACTIVATION ANALYSIS OF ALUMINIUM, VANADIUM, COPPER, MOLYBDENUM, ZINC AND URANIUM IN NATURAL WATER SAMPLES USING ORGANIC COPRECIPITANTS

A method is described for the determination of trace metal ions, V, Al, Cu, Mo Zn, and U, in natural water samples by neutron activation analysis, using organic coprecipitation as a preconcentration method. The preconcentration of trace elements was accomplished by converting the dissolved trace metal ions into the oxine chelates atpH 5.2 and extraction of the chelates witho-phenylphenol which is a liquid above 56 °C and solidifies at room temperature. After cooling the extraction system, the fine particles of the organic phase were collected on a millipore filter and the precipitate was air-dried in a clean environment. The solid extract was wrapped up in a sheet of clean polyethylene and subjected to neutron irradiation in a reactor for less than 10 min at a thermal flux of 2·1013 n·cm−2·sec−1. γ-Ray spectrometry by a coaxial Ge(Li) detector connected to a 1024-channel PHA was performed on the irradiated sample without further chemical separation, and thus the ppb level concentration of the elements in natural water samples could be determined. The fundamental study of the collection of the trace elements is also described.

Radioactivation analysis of hair a means of biological monitoring of the environment

With the aim of indicating environmental pollution effects by heavy metals on humans using hair, nondestructive activation analysis was applied to 382 normal Japanese hair samples (background level). Elemental contents of hair could be determined for Ag, Al, As, Br, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, I, K, La, Mg, Mn, Na, S, Sb, Sc, Se, Sm, Ti, V and Zn. As these elements in hair have wide concentration ranges, the differences in concentrations distribution between groups (sex, age, permanent treatment and regional difference) are discussed. A method for hair sampling is presented.

Neutron activation analysis of biologically essential trace elements in environmental specimens using pyrrolidinedithiocarbamate extraction

A new radiochemical group separation method using APDC reagent in the extraction procedure has been developed. The method has been applied to the radiochemical separation for activated biological samples and also to the preconcentration technique for sea water samples. The transition elements are extracted into chloroform phase from the pH 3.0 aqueous phase and only manganese is subsequently extracted from the pH 7.0 aqueous phase. The validity of the method is demonstrated by analyzing the NBS standard reference materials. In the specimens preconcentrated from the sea water samples adjusted pH to 5.5, vanadium, manganese, copper and zinc can be determined.

Multielement analysis of groundwater samples by neutron activation with comparison between direct and evaporation methods

This report is the results of the studies on NAA of groundwater samples with comparison between direct and evaporation methods, and of the applications for the samples of alluvium plain composed with granitiform soils and of Neogene strata composed with clay minerals.

Emission spectrographic determination of trace elements in atmospheric particulate matter

Abstract Air containing particulate material was passed continuously for one month through a low-volume air sampler equipped with a cyclone to exclude particulates greater than 10 μm in diameter. The samples and filters were ashed in a low-temperature plasma and, after addition of In2O3 support, palladium internal standard and graphite buffer, the ashes were analyzed by a.c. are emission spectrometry. Standard samples were prepared from a commercial standard containing 49 elements. The procedure allows the determination of 14 trace metals (Ag, Al, Cr, Cu, Fe, Ga, Mn, Mo, Ni, Pb, Sn, Ti, V, Zn) with relative standard deviations of 1.4–15.1%. The procedure has been applied successfully to monthly determinations of the average atmospheric concentrations of these elements in Kobe City for the past three years.

Selenium Intake for Infants Immediately After Delivery

Abstract Selenium content of colostral milk and mature milk in 5 months after birth was determined by fluorometry with 2,3- diaminonaphthalene. In the first milk after birth selenium was contained to be the highest amounts of 29.4 ng/g but selenium concentration decreased to about 9 ng/g after the birth of 1 week. In the lactation period of 10 to 171 days, the concentration was almost constant to be 9.0 ± 1.2 ng/g. The content of infant formulas (milk powder for young infants) based on cows milk was 42.9 ± 8.4 ng/g corresponding to 6.0 ± 1.2 ng/ml in the liquid milk prepared for lactation. Therefore selenium intake was calculated to be about 17 μg/d in the colostral milk-feeding infants after delivery and about 8 μ g/d in mature milk-feeding infants at the age of more than 1 month after birth, whereas it was 3 -6 μ g/d in formula-feeding infants.