Uranium, determination calcium

The methods involving GBHA have been applied for determining calcium in milk [68], soil, plant material, and natural waters [69], uranium [70], silicate minerals [71], and lithium and barium salts [27]. 

Le Cornec, E, and Correge,T. (1997). Determination of uranium to calcium and strontium to calcium ratios in corals by inductively coupled plasma mass spectrometry. J. Anal. At. Spectrom. 12(9), 969. 

Vanadate, dioxybis(oxamato)-bond-length ratios, 1,57 Vanadate, heptacyano-potassium salt structure, I, 72 Vanadate, hexafluoro-dipotassium salt history, I, 21 potassium salt history, 1,21 tripotassium salt history, 1,21 Vanadate, pentachloro-stereochemistry, 1,40 Vanadate, pentafluorooxy-stereochemistry, I, 50 Vanadates biochemistry, 3,456 calcium/magnesium ATPase inhibition, 6, 567 competition with phosphates physiology, 6,665 protonation, 3,1026 sodium pump, 6, 557 in uranium purification from ore, 6, 899 Vanadates, hexafluoro-, 3. 482,531 Vanadates, oxoperoxo-, 3,501 Vanadates, pentacarbonyl-, 3, 457 Vanadium biology, 6,665 determination, 1. 548 extraction... 

To the filtered seawater (500 ml about 1.5 xg U) is added 0.05 M ferric chloride (3 ml), the pH is adjusted to 6.7 0.1 and the uranium present as (U02(C03)3)4- is adsorbed on the colloidal ferric hydroxide which is floated to the surface as a stable froth by the addition of 0.05% ethanolic sodium dodecyl sulfate (2 ml) with an air-flow (about 10 ml min-1) through the mixture for 5 min. The froth is removed and dissolved in 12 M hydrochloric acid-16 M nitric acid (4 1) and the uranium is salted out with a solution of calcium nitrate containing EDTA, and determined spectrophotometrically at 555 nm by a modification of a Rhodamine B method. The average recovery of uranium is 82% co-adsorbed WO4- and M0O4- do not interfere. 

The atomic absorption characteristics of technetium have been investigated with a technetium hollow-cathode lamp as a spectral line source. The sensitivity for technetium in aqueous solution is 3.0 /ig/ml in a fuel-rich acetylene-air flame for the unresolved 2614.23-2615.87 A doublet under the optimum operating conditions. Only calcium, strontium, and barium cause severe technetium absorption suppression. Cationic interferences are eliminated by adding aluminum to the test solutions. The atomic absorption spectroscopy can be applied to the determination of technetium in uranium and its alloys and also successfully to the analysis of multicomponent samples. 

A study by the oral route establishing a threshold for renal effects in weanling and adult rats of the same strain is needed to determine if susceptibility to uranium toxicity varies with age. Histopathological studies and urinalysis should be performed, as well as measurement of uranium in excreta for both groups. At termination in this study, uranium content should be measured in tissues, particularly bone and kidney. This will provide information on whether retention of uranium in bone is age-dependent (as assumed by analogy with calcium in PBPK models) and on whether kidney burden associated with uranium toxicity is age-related. 

Lithophile elements such as magnesium, potassium, calcium, rubidium, strontium, the rare earth elements, and uranium (9) are not expected to be mobilized during oil shale retorting. Many of these elements can be determined quite precisely at trace element levels. Thus, investigation of the values of ER and RI for these elements should help to establish the reliability of the ER and RI values. 

Atomization of the sample is usually facilitated by the same flame aspiration technique that is used in flame emission spectrometry, and thus most flame atomic absorption spectrometers also have the capability to perform emission analysis. The previous discussion of flame chemistry with regard to emission spectroscopy applies to absorption spectroscopy as well. Flames present problems for the analysis of several elements due to the formation of refractory oxides within the flame, which lead to nonlinearity and low limits of detection. Such problems occur in the determination of calcium, aluminum, vanadium, molybdenum, and others. A high-temperature acetylene/nitrous oxide flame is useful in atomizing these elements. A few elements, such as phosphorous, boron, uranium, and zirconium, are quite refractory even at high temperatures and are best determined by nonflame techniques (Table 2). 

Finally, it should be noted that just as a typical " °Ar- Ar irradiation also produces argon from calcium and chlorine, a typical I-Xe irradiation also produces xenon from tellurium, barium and uranium (Turner 1965) and krypton from bromine. Conversion factors for many or all of these reactions have been measured or calculated by several authors, most recently by Irwin and co-workers for use in studies of fluid inclusions (Irwin and Reynolds 1995 Irwin and Roedder 1995). Many of these elements are not routinely determined by other techniques, so direct comparisons with other techniques are rare (but see (Garrison et al. 2000 Swindle et al. 1991b)). 

Major Applications Nanocomposite material, chemical mechanical polishing, optical fibers, display device, carbon nanombes, ° textiles," determination of aluminum, iron," copper, manganese, zinc, calcium, magnesium, zirconium, hafnium, molybdenum, uranium, vanadium, detergents, hair dyes, determination of proteins, clotrimazole, ketoconazole, piroxicam, and tenoxicam ... 

Fission track geochronology is a method for dating minerals containing uranium, particularly apatites and zircon. Apatite is a calcium phosphate that is common in granites and metamorphic rocks. Zircon is a zirconium silicate that is also common in similar rocks. The sample age is determined by counting fission tracks in the material from spontaneous fission of These tracks are a function of the U content and the age since closure when the fission track clock started. A research reactor is then used to irradiate the samples and induce fission in the present in the sample. By comparison of the before and after track count, the U content in the sample is determined. 

---