| Budget Amount *help |
¥6,800,000 (Direct Cost: ¥6,800,000)
Fiscal Year 1986: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1985: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1984: ¥3,000,000 (Direct Cost: ¥3,000,000)
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| Research Abstract |
After spiking with <^(107)Ag> , <^(116)Cd> , <^(65)Cu> , <^(61)Ni> , <^(206)Pb> , <^(203)Tl> and <^(68)Zn> , the spiked sample was decomposed in a mixture of <HNO_3> ,HC <10_4> and HF at low temperature under pressure. The decomposed sample was heated to dryness and the residue obtained was dissolved in a dilute <HNO_3> solution. The heavy metals were extracted from an aliquot of the solution as their dithizonates into chloroform and applid to the mass spectrometer(Hitachi RMU-6) equipped with a surface ionization device incorporating a Re single filament.
Their concentrations in the sample could be successively determined by measuring <^(205)Tl> / <^(203)Tl> , <^(109)Ag> / <^(107)Ag> , <^(63)Cu> / <^(65)Cu> , <^(114)Cd> / <^(116)Cd> , <^(208)Pb> / <^(206)Pb> , <^(58)Ni> / <^(61)Ni> and <^(66)Zn> / <^(68)Zn> with raising ionization temperature. The present method could measure minute amounts, i.e., <10^(-9)> - <10^(-11)> g of the above elements with an accuracy of 1%.
Samples were all pr
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epared in a ultra clean draft chamber and on benches set in a class 100 pressurized room,the latter being constructed of stainless steel double walls and having a methoxy-resin covered floor. Reagents and water were all purified by sub-boiling distillation method.
The mass spectrometer could detect an emitter current of <10^(-19)> A for the mass spectrum emitted by an element and measure the isotopic ratio with an accuracy of 0.1% in the coefficient of variations.
The spikes were imported from the Oak Ridge National Laboratory, Tenn., U.S.A., and each spike was dissolved in a dilute <HNO_3> solution and stored in a tightly stoppered teflon or quartz bottle. The isotopic abundance and molar concentration of every spike were standardized to the reference materials. The working composite spike solution was prepared by mixing the stock solutions just prior to the use.
The method has been applied with a good success to the environmental samples such as rocks,plants,animals,Polar ice and oceanic waters as well as industrial materials. Less
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