Strontium determination

Starch as sample diluent, 173 Steel strip, x-ray gaging, 69-71 Strontium, determination by x-ray emission spectrography, 329 in solution, discussion of background in x-ray emission spectrography, 213, 214... 

Mateos, J. J., Gomez, E., Garcias, F., Casas, M., and Cerda, V., Implementation of a sequential injection pre-treatment method for simultaneous radium and strontium determination, Int. J. Environ. Anal. Chem., 83, 515-521, 2003. 

For strontium determinations samples, standards and blanks are made to 1% (m/v) in lanthanum to prevent the formation of refractory compounds. Analyses for strontium also suffer from ionisation interferences which are discussed later. 

Strontium determinations in soils, sea water, etc., have the same topicality as similar determinations in biological materials. The strontium and barium content of a number of soils and plants has been determined by Bowen and Dymond (5). They found that strontium was preferentially absorbed with respect to calcium by plants from most of the )ils considered while barium was taken up much less readily. 

Waters containing strontium mostly have a high calcium content as well. Consequently, the effect of calcium, intensifying the emission of strontium must be compensated for. In practical water analysis calcium is always determined in conjunction with strontium determination. For this purpose, in a separate preparation a quantity of calcium carbonate is weighed in... 

Other examples of automatic radiochemical methods with offline detection are automatic methods for stable and radioactive strontium determination [28,29]. In these works two detectors were proposed, ICP-OES and a LBPC, to measure stable and radioactive strontium isotopes, respectively. 

The concentration of strontium in a sea water aquarium is determined by atomic absorption using the method of... 

Samples of animal bones weighing approximately 3 g are ashed at 600 °C until the entire bone is ash-white. Samples are then crushed in a mortar and pestle. A portion of the sample is digested in HCl and diluted to a known volume. The concentrations of zinc and strontium are determined by atomic absorption. The analysis for strontium illustrates the use of a protecting agent as La(N03)3 is added to prevent an interference due to the formation of refractory strontium phosphate. 

Rubidium-87 emits beta-particles and decomposes to strontium. The age of some rocks and minerals can be measured by the determination of the ratio of the mbidium isotope to the strontium isotope (see Radioisotopes). The technique has also been studied in dating human artifacts. Rubidium has also been used in photoelectric cells. Rubidium compounds act as catalysts in some organic reactions, although the use is mainly restricted to that of a cocatalyst. 

The chemical identities of the fission products determine their subsequent redistribution, those elements which are in the gaseous state at the temperature of the operation migrating to the cooler exterior of the fuel rods, and die less voltile elements undergoing incorporation in the fuel rod in solid solution. Thus caesium and iodine migrate to the gas fill which sunounds the fuel rod, and elements such as the rare earths and zirconium are accommodated in solid solution in UO2 without significant migration along the fuel rod radius. Strontium and barium oxidize to form separate islands which can be seen under the microscope. 

Thermogravimetry may be used to determine the composition of binary mixtures. If each component possesses a characteristic unique pyrolysis curve, then a resultant curve for the mixture will afford a basis for the determination of its composition. In such an automatic gravimetric determination the initial weight of the sample need not be known. A simple example is given by the automatic determination of a mixture of calcium and strontium as their carbonates. 

Determination of barium as sulphate Discussion. This method is most widely employed. The effect of various interfering ions (e.g. calcium, strontium, lead, nitrate, etc., which contaminate the precipitate) is dealt with in Section 11.72 The solubility of barium sulphate in cold water is about 2.5 mg L"1 it is, however, greater in hot water or in dilute hydrochloric or nitric acid, and less in solutions containing a common ion. 

Determination of strontium as strontium hydrogenphosphate, SrHP04 Discussion. 

Fluoride, in the absence of interfering anions (including phosphate, molybdate, citrate, and tartrate) and interfering cations (including cadmium, tin, strontium, iron, and particularly zirconium, cobalt, lead, nickel, zinc, copper, and aluminium), may be determined with thorium chloranilate in aqueous 2-methoxyethanol at pH 4.5 the absorbance is measured at 540 nm or, for small concentrations 0-2.0 mg L 1 at 330 nm. 

Thus, for example a solution containing potassium ions at a concentration of 2000 mg L "1 added to a solution containing calcium, barium, or strontium ions creates an excess of electrons when the resulting solution is nebulised into the flame, and this has the result that the ionisation of the metal to be determined is virtually completely suppressed. 

The determination of magnesium in potable water is very straightforward very few interferences are encountered when using an acetylene-air flame. The determination of calcium is however more complicated many chemical interferences are encountered in the acetylene-air flame and the use of releasing agents such as strontium chloride, lanthanum chloride, or EDTA is necessary. Using the hotter acetylene-nitrous oxide flame the only significant interference arises from the ionisation of calcium, and under these conditions an ionisation buffer such as potassium chloride is added to the test solutions. 

Strontium oxalate shall be free of barium compounds, and shall contain not more than a slight amount of calcium compds. Conformance with these requirements shall be determined by... 

Determination of Barium and Strontium Peroxides (Active Oxygen) in Igniters In Small Arms Tracer Ammunition , FATR T-76059 (1975) 33) ChemRubHndbk (1975), B-71... 

Recognition among bone-chemistry researchers that strontium enters bone in proportion to dietary levels has resulted in widely accepted yet erroneous inferences about the relationships among various elements in bone and past diet. One such inference is that more of any element in the diet translates directly to more of that element in bone. If an element is not biogenically incorporated within bone, or if biological levels are metabolically controlled, then that element will not reflect diet. A second erroneous inference is that strontium can be used to measure the dietary plant/meat ratio. Sr/Ca ratios in meat are generally lower than those of plants, but meat is also low in calcium and hence has little effect on the composition of bone. Plants, on the other hand, contribute substantially to bone composition. Variations in the strontium levels of bone thus more likely reflect differential consumption of plants rather than trophic position. Although efforts to determine plant/meat ratios from strontium and to draw dietary inferences from elements other than strontium and barium have not been successful, this failure has been due to inappropriate expectations, not to a failure of bone strontium to reflect diet. 

Although there are many failed attempts to determine even relative measures of meat eonsumption, the disappointment is not due to any failure of strontium to reflect diet but to an unwarranted expectation that bone strontium should necessarily reflect meat consumption. The frustration with efforts to draw paleodietary inferences stems from simplistically equating Sr/Ca ratios with plant/meat ratios and to the inappropriate use of elements not... 

Guogang J, Testa C, Desideri D, et al. 1998. Sequential separation and determination of plutonium, americium-241 and strontium-90 in soils and sediments. J Radioanal Nucl Chem 230(l-2) 21-27. 

Example Feasible Region Determination and Rescaling. McLean and Anderson (9) described a mixture experiment in which magnesium (X ), sodium nitrate (X2), strontium nitrate (X3), and binder (X ) were combined and ignited to produce flares varying in intensity. The four components had the following ranges ... 

Impact sensitivities of mixtures of red phosphorus with various oxidants were determined in a direct drop-ball method, which indicated higher sensitivities than those determined with an indirect striker mechanism. Mixtures with silver chlorate were most sensitive, those with bromates, chlorates and chlorites were extremely sensitive, and mixtures with sodium peroxide and potassium superoxide were more sensitive than those with barium, calcium, magnesium, strontium or zinc peroxides. Mixtures with perchlorates or iodates had sensitivities comparable to those of unmixed explosives, such as lead azide, 3,5-dinitrobenzenediazonium-2-oxide etc. 

The presence of normal concentrations of sodium, magnesium, and strontium have no net effect on the determination of calcium above the approximate level of accuracy of about 0.1% so that no correction factor seems necessary. A sufficient amount of titrant must be added to complex at least 98% of dissolved calcium before the buffer is added this apparently reduces the loss of calcium by coprecipitation with magnesium hydroxide. 

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