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1.
An isotope exchange method for the speciative determination of phosphorus (PO 4 3– , PO 3 3– and total P) in natural water samples is proposed by using the exchange system of moly bdophosphate in the aqueous phase and tetraphenylarsonium molybdophosophate in the organic phase. In this exchange system, only PO 4 3– exchanges and is determined. When the sample water is treated with Br2 water in advance, the amount of PO 4 3– +PO 3 3– can be obtained. When the sample is treated with H2SO4 and HNO3, then the amount of total P can be determined.  相似文献   

2.
3.
A radiochemical separation procedure has been developed to determine traces of phosphorus in gallium arsenide. In this procedure the indicator nuclide32P is separated from all other long-lived activation products in high purity. The resulting eluate is sufficiently pure to allow -counting. Because of the high -energy of32P (1710 keV) the activity can be measured via the Cerenkov effect, whereas most radionuclides, because they have essentially lower -energies, are discriminated by this technique, so that the selectivity of the measurement of32P is improved considerably. A detection limit of 1 ng/g was achieved when using samples of 50 mg, a thermal neutron flux of th=1·1013n·cm–2·s–1, an irradiation time of 36 hours and a measuring time of 1 hour.  相似文献   

4.
Summary A simple, sensitive, accurate and rapid gas chromatographic method for the quantitative determination of phosphorus in copper-phosphorus alloys is described. The method is based on the chlorination of the sample with carbon tetrachloride in a sealed glass capsule at 550°C. The volatile products are introduced into the gas chromatograph after crushing the capsule in a special device. The method is very quick (ca. 20 min), involves simple manipulations and the error is about ±0.5%.  相似文献   

5.
Mukai K 《Talanta》1972,19(4):489-495
A reproducible method is described for determination of small amounts of phosphorus (from 0.0005% to 0.02%) in hypereutectic aluminium-silicon complex alloys. The method permits the separate determination of phosphorus in acid-soluble and acid-insoluble fractions. Phosphomolybdate is extracted with n-butanol-chloroform solvent mixture and back-extracted with a btannous chloride reducing solution. The phosphorus content of a sample cut into small pieces decreases during storage; loss of phosphorus is negligible on acid dissolution under oxidizing conditions.  相似文献   

6.
A new radioanalytical method has been developed based on homogeneous isotopic exchange in the organic phase. The theory of the method is presented and discussed. This method has been applied for the simple, selective and rapid determination of bismuth based on the isotopic exchange between bismuth diethyldithiocarbamate and bismuth iodide complex labelled with210Bi. As little as 0.01 μg of the metal can be determined.  相似文献   

7.
Summary A method for the isotope dilution mass spectrometric (IDMS) determination of boron in rye grass at the 5 g · g–1 level has been developed. The mass spectrometric measurements are performed using negative thermal ionization at masses 42 (10B16O16O) and 43 (11B16O16O). The 10B/11B ratios are corrected for the 10B16O17O contribution at mass 43 and for mass fractionation. The chemical blank is determined using the standard addition method. The numerical calculations are done with a least square fit computer program. The method has been applied for the certification of boron in BCR 281 (Rye Grass). The boron content of this reference material has been established as (5.64±0.56) g·g–1.
Bestimmung von Borspuren in Rye Grass BCR 281 durch Isotopenverdünnungs-Massenspektrometrie
  相似文献   

8.
A radiometric method for the determination of cadmium based on two-phase isotope exchange has been developed. The sample containing cadmium is shaken in the presence of tartrate with a standard cadmium-115m diethyldithiocarbamate solution in chloroform. From the distribution of the activity between the aqueous and organic phases 0.05–7 g of cadmium in 5–20 ml sample can be determined.Dedicated to Prof. V. D. Nefedov on the occasion of his 70th birthday  相似文献   

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10.
There is need for a rapid method for the determination of moderate amounts of boron in titanium alloys. In this paper a method is proposed which uses ion exchange. The method is applicable to titanium alloys containing 0.025 to 1 per cent. boron. One or two grams of the sample are dissolved in hydrochloric acid, and the titanium and boron are oxidized with nitric acid. The bulk of the titanium is removed by a cation exchanger. A calcium carbonate separation is made to remove the residual titanium and adjust the acidity. The boron is then titrated with sodium hydroxide, after the addition of mannitol. None of the elements found in commercial titanium alloys interferes with the method.  相似文献   

11.
Some water-soluble organic iodine compounds (aqueous solution) can be analyzed for iodine by isotopically exchanging with labelled elementary iodine (organic solution). The method is applicable to exchange systems in which the rate of the exchange is rather small but measurable, before the exchange equilibrium is attained. The iodine content of iodoaromatic amino acids such as 5-iodouracil and 3,5-diiodotyrosine can be determined within an error of ±4%.  相似文献   

12.
Kujirai O  Kobayashi T  Ide K  Sudo E 《Talanta》1983,30(1):9-14
Traces of selenium in complex nickel- and cobalt-based heat-resisting alloys have been determined by co-precipitation and graphite-furnace atomic-absorption spectrometry. The alloys are dissolved in a mixture of concentrated hydrochloric acid, concentrated hydrofluoric acid and 30% hydrogen peroxide. Selenium does not volatilize to any significant extent during the dissolution and concentration. Selenium is separated from the matrices as the element by co-precipitation with arsenic and is redissolved in nitric acid. Zinc is added to the solution to stabilize selenium during the ashing step and thus to enhance the absorbance in the atomization step. Standard solutions for the calibration are prepared in a similar manner to sample solutions after dissolution of the arsenic carrier. The detection limit for selenium is 0.3 ppm in the heat-resisting alloy.  相似文献   

13.
Kujirai O  Kobayashi T  Ide K  Sudo E 《Talanta》1982,29(1):27-30
A simple analytical method has been developed for the determination of traces of Te in complex heat-resisting alloys by graphite-furnace atomic-absorption spectrometry. Nickel-base and cobalt-base heat-resisting alloys are dissolved in concentrated hydrochloric and hydrofluoric acids plus 30% hydrogen peroxide. Tellurium is separated from the matrix by co-precipitation with As and dissolved in nitric acid. Memory effects are eliminated by the oxidation of Te(IV) to Te(VI). Standard solutions for the calibration are prepared by the procedure used for the sample solution. The detection limit for Te is 0.05 ppm in the alloy.  相似文献   

14.
On the one hand, 19-norandrosterone (NA) is the most abundant metabolite of the synthetic anabolic steroid 19-nortestosterone and related prohormones. On the other hand, small amounts are biosynthesized by pregnant women and further evidence exists for physiological origin of this compound. The World Anti-Doping Agency (WADA) formerly introduced threshold concentrations of 2 or 5 ng of NA per ml of urine to discriminate 19-nortestosterone abuse from biosynthetic origin. Recent findings showed however, that formation of NA resulting in concentrations in the range of the threshold levels might be due to demethylation of androsterone in urine, and the WADA 2006 Prohibited List has defined NA as endogenous steroid. To elucidate the endogenous or exogenous origin of NA, (13)C/(12)C-analysis is the method of choice since synthetic 19-nortestosterone is derived from C(3)-plants by partial synthesis and shows delta(13)C(VPDB)-values of around -28 per thousand. Endogenous steroids are less depleted in (13)C due to a dietary mixture of C(3)- and C(4)-plants. An extensive cleanup based on two high performance liquid chromatography cleanup steps was applied to quality control and doping control samples, which contained NA in concentrations down to 2 ng per ml of urine. (13)C/(12)C-ratios of NA, androsterone and etiocholanolone were measured by gas chromatography/combustion/isotope ratio mass spectrometry. By comparing delta(13)C(VPDB)-values of androsterone as endogenous reference compound with NA, the origin of NA in doping control samples was determined as either endogenous or exogenous.  相似文献   

15.
An isotope dilution mass spectrometric method has been developed for the precise determination of 3–300 p.p.m. of sulfur in nickel-base alloys and alloy steels. The sample is dissolved in mixed acids, a spike is added, and nitrate ions are removed. Sulfate is reduced with a mixture of hydriodic, hypophosphorous, and hydrochloric acids; the hydrogen sulfide evolved is absorbed in cadmium acetate solution and converted to silver sulfide, which is burned to sulfur dioxide, for the isotope analysis. The relative standard deviation at the 50-p.p.m. level for 1-g samples is less than 3 %.  相似文献   

16.
The catalysed isotope exchange method was studied with the aim to elaborate the optimal procedure for labeling of amitriptyline with iodine125I. Besides the catalysts published, cuprous salts and ammonium sulphate, a series of transition metal complexes as catalysts were tested at different reaction conditions. The best result (91% radiochemical yield) was achieved with trans-chlorocarbonylbis-(triphenylphosphine) iridium complex (Vaska catalyst) and sonification.  相似文献   

17.
A general method is presented for the spectrophotometric determination of phosphorus at trace levels. It involves extraction of the yellow molybdophosphoric acid with isobutyl acetate and subsequent reduction to heteropoly blue. The method covers the range 0.2–20 μg of phosphorus. A comprehensive study of interferences using standard additions of 10 and 20 μg of phosphorus was carried out and modifications are described to permit the determination of phosphorus in a wide variety of metals and salts.  相似文献   

18.
《Talanta》1963,10(11):1153-1157
A neutron-activation analysis method for the determination of traces of iron in samples of purified platinum is described. The nuclear reactor BEPO at Harwell has been used as the neutron source. A rapid radiochemical separation procedure using carriers has been employed to decontaminate the iron activity from most other induced activities. The analysis is completed by discriminated γ-scintillation counting. Results of analyses of seven samples of platinum are quoted. The method of analysis has the advantage that it obviates difficulties caused by “reagent blanks” or by contamination from traces of inactive iron after irradiation. Interference resulting from nuclear reactions of elements other than iron in the samples appears to be of no consequence in the present case.  相似文献   

19.
《Talanta》1963,10(9):987-990
A neutron-activation analysis method for the determination of traces of cobalt in samples of purified platinum is described. Using a pile flux of 1.2 × 1012 thermal neutrons. cm−2. sec−1, as little as 10−9 g of cobalt may be determined. A rapid radiochemical separation procedure coupled with gamma-ray spectrometry permits measurement of 5.26-year cobalt-60 activity. Results of analysis of seven samples of platinum are quoted.  相似文献   

20.
《Talanta》1962,9(4):349-353
A neutron-activation method has been developed for determining small amounts of ruthenium impurity in samples of platinum. The Harwell nuclear reactor BEPO has been used as the source of neutrons. The procedure depends on the chemical separation of radioactive ruthenium, with added ruthenium carrier, from irradiated samples and standards. Results are quoted for the ruthenium contents of a number of samples of platinum.  相似文献   

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