Strontium phosphate

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. 

Brash, D. E., R. R. Reddel, M. Quanrud, K. Yang, M. P. Farrell, and C. C. Harris. 1987. Strontium phosphate transfection of human cells in primary culture Stable expression of the simian virus 40 large-T-antigen gene in primary human bronchial epithelial cells. Mol Cell Biol 7(5) 2031-4. 

Among condensed phosphate systems with polyvalent cations, the very complicated calcium salts have been much studied and a great number of compounds have been detected, often with several modifications (5, 27, 28, 34, 54, 79, 186, 137, 191, 198, 204, 211, 276, 805, 830). In this system special interest attaches to the occurrence of crystalline cross-linked phosphates (see Section V) and of calcium pentaphosphate, CayiPsOis (see Section IV,D,/). The end-product obtained by heating Ca(H2P04)2 in the free atmosphere is the high-molecular calcium polyphosphate, which crystallizes in several forms. The condensed strontium phosphates (246, 805) are similarly complicated and cannot readily be made the subject of a brief review. 

C—F 7.(a) 1.26, non-polar molecule (b) 0.97, polar molecule (c) 1.55, non-polar molecule 3.4 1.(a) potassium chromate (b) ammonium nitrate (c) sodium sulfate (d) strontium phosphate (e) potassium nitrite (f) barium hypochlorite 2.(a) magnesium chloride (b) sodium oxide... 

The tri-calcium, barium, and strontium phosphates are members of an isostructural series M3(P04)2, where M = Ca, Ba, Sr, etc. The minerals formed by Ca are very important in bioceramics, and because Ba and Sr are fission products (i.e., formed as by-products in nuclear reactions), apatite minerals play a major role in their stabilization for disposal (see Chapter 17). Within these common structures, however, calcium phosphate goes through several phase changes at different temperatures. These phases are labeled as (3, a, a, etc. The reader is referred to Refs. [1,2] for details. 

Strontium phosphate partly with barium phosphate [5.83]... 

Zinc-free aluminum phosphates with strontium phosphate [5.75]... 

The strontium preconcentration by coprecipitation of calcium and strontium phosphates requires magnetic stirrers with heating plate and a centrifuge collecting the precipitate. A drying cabinet is used to gently dry the precipitate of calcium and strontium phosphates. 1220 Quantulus counter is routinely used for the determination of low-level radioactivities. 

The sample is mixed and heated to 80-90 °C on a magnetic stirrer. Then precipitation of calcium and strontium phosphates in alkaline medium (pH = 8 - 9) is performed by adding concentrated ammonium hydroxide. Precipitate is allowed to settle for at least 2 hours to one night. Then the supernatant is discarded. The precipitate is collected in a centrifuge tube and rinsed with alkalized water. Precipitate is dried in a warm atmosphere at 80°C. 

For those interested in mineral matter in coal, an awareness that some partings may be of volcanic origin may be useful in explaining the distribution of some of these layers and the occurrences of some unusual components, such as strontium, phosphate, or uranium. Volcanic ash partings are likely to be more widespread and uniform in texture, composition and thickness than the more common partings of fluvial origin. They are also more likely to show marked differences from layer to layer, and to contain exotic mineral or chemical components. 

By use of releasing agents Considering the reaction M-X-i-R = R- Xh-M, it becomes evident that an excess of the releasing agent (R) will lead to an enhanced concentration of the required gaseous metal atoms (M) which will be of special significance if the product R-X is a stable compormd. Hence in the determination of calcium in presence of phosphate the addition of excess of strontium chloride to the test solution will lead to the formation of strontium phosphate and the calcium can then be determined in an acetylene-air flame without any interference due to phosphate. Also addition of EDTA to a calcium solution before analysis may increase the sensitivity of the subsequent flame spectrophotometric determination which may be due to the formation of an EDTA complex of calcium which is readily dissociated in the flame. 

No studies were located regarding cardiovascular effects after acute- or chronic-duration oral exposure in animals. In male weanling Wistar rats (5-6 per group) given strontium as strontium phosphate in the diet for 4-6 weeks, hemorrhage (unspecified) occurred at 2,820 mg strontium/kg/day, possibly related to the increased mortality at this dose level, but not at or below 1,270 mg Strontium/kg/day (Kshirsagar 1976). 

Stable Strontium. There is no evidence regarding the effect of stable strontium on reproduction, but levels of exposure possible by inhalation or dermal routes are not likely to be harmful. Stable strontium was found to have beneficial effects when it was used in solutions designed for testing the functional capacity of human spermatozoa in vitro (Mortimer 1986 Mortimer et al. 1986). The possible consequences of excess strontium ingestion on reproduction need to be explored. Such experiments should compare the relative toxicity of stable strontium compounds that have different properties and may have different rates of absorption, e.g., strontium chloride, strontium carbonate and strontium phosphate. 

Property Strontium fluoride Strontium hydroxide Strontium nitrate Strontium phosphate Strontium oxide... 

Mayer I, Swissa S (1985) Lead and strontium phosphate apatites substituted by rare earth and silver ions. J Less Coimnon Metals 110 411-414... 

Leroux L, Lacout JL (2001a) Synthesis of calcium-strontium phosphate fluor-hydroxylapatites by neutralisation. Phosph Sulf Sil Rel Elements 173 27-38 Leroux L, Lacout JL (2001b) Preparation of calcium strontium hydroxylapatites by a new route involving calcium phosphate cements. J Mater Res 16 171-178... 

Phosphoric acid, monophenyl ester. See Phenyl acid phosphate Phosphoric acid monopotassium salt. See Potassium phosphate Phosphoric acid monosodium salt. See Sodium phosphate Phosphoric acid, pure. See Phosphoric acid Phosphoric acid, strontium salt. See Strontium phosphate Phosphoric acid tributyl ester Phosphoric acid, tri-n-butyl ester. See Tributyl phosphate... 

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