Magnesium analysis

Because the production of magnesium is a large-scale iadustrial process, fast and rehable methods for magnesium analysis have been developed for the quick turnaround times necessary ia a production foundry (76,77). Referee methods which are more time consuming but have larger ranges and greater accuracy compared to the production methods have also been developed (78). 

Hardness (calcium and magnesium) analysis, of water, 26 37 Hardness measurements, for steel,... 

Reentrant cardiac rhythms, 5 82, 86, 87-88 Reentrant nematic phase, 15 102 Referee methods, of magnesium analysis, 15 348... 

Commercial primary magnesium has a typical purity of 99.8%, which is sufficient for most chemical and metallurgical uses. A typical analysis might be expected to show about 0.003% each of aluminum and copper, 0.04% iron, 0.08% manganese, 0.001% nickel, and 0.005% siHcon. Primary magnesium is available in five grades (Table 3). Considerably higher purity can be obtained by distillation. 

Referee Methods. The American Society for Testing Materials (ASTM) has collected a series of standard referee methods for the analysis of magnesium and its alloys (78). These methods are accurate over a larger range of concentration than the production methods, but are time consuming ia thek apphcation. The methods are based on potentiometric titration, photometric methods, or gravimetric methods. The photometric methods are most common and are relatively straightforward. 

Standard Test Methods For Chemical Analysis of Magnesium and Magnesium Alloys, ASTM E-35 to 88, American Society for Testing and Materials, Philadelphia, Pa., 1992. 

Ion-selective electrodes are available for the electro analysis of most small anions, eg, haUdes, sulfide, carbonate, nitrate, etc, and cations, eg, lithium, sodium, potassium, hydrogen, magnesium, calcium, etc, but having varying degrees of selectivity. The most successful uses of these electrodes involve process monitoring, eg, for pH, where precision beyond the unstable reference electrode s abiUty to deUver is not generally required, and for clinical apphcations, eg, sodium, potassium, chloride, and carbonate in blood, urine, and semm. 

M. A. IT insky and G. Knorre proposed l-nitroso-2-naphthol as a reagent for cobalt and Zh.I. lotsich - magnesium diiodine acetylene as a reagent for carbonyl group. F.M. Flavitsky developed a method for qualitative analysis based on solid substances as well as a portable laboratory for qualitative analysis. G.V. Khlopin proposed a method for determining oxygen dissolved in water. 

COMBINED APPLICATION OF COMPOSITION AND STRUCTURE ANALYSIS METHODS TO THE DETERMINATION OF MAGNESIUM CONCENTRATION AND LOCATION IN BONE... 

In report discuss the methodical aspects determination of magnesium, manganese, cobalt, zinc to their joint presence in nitric, sulphuric, chloric salts, and peculiarity of the analysis using to solid solutions of the hydrated diphosphates. 

This procedure was tested in the analysis of pharmaceutical products Poltava s bishofite (series Elite and Profi ) and a brine of bischofite with rusty precipitate. The data bear out the sufficient accuracy and reproducibility of the proposed procedure which allows to perform the determination magnesium, iron, copper and zinc ions at concentrations above 10 M. It was found that the content of Mg ion in the studied brine decreases in comparison with Poltava s bishofite . The Fe, Cu and Zn ions were not detected in the brine. 

X-ray analysis of material scraped from internal surfaces indicated that it was 88% iron, 7% silicon, and 1% each of magnesium, aluminum, chlorine and sulfur. 

The solubility of the precipitates encountered in quantitative analysis increases with rise of temperature. With some substances the influence of temperature is small, but with others it is quite appreciable. Thus the solubility of silver chloride at 10 and 100 °C is 1.72 and 21.1mgL 1 respectively, whilst that of barium sulphate at these two temperatures is 2.2 and 3.9 mg L 1 respectively. In many instances, the common ion effect reduces the solubility to so.small a value that the temperature effect, which is otherwise appreciable, becomes very small. Wherever possible it is advantageous to filter while the solution is hot the rate of filtration is increased, as is also the solubility of foreign substances, thus rendering their removal from the precipitate more complete. The double phosphates of ammonium with magnesium, manganese or zinc, as well as lead sulphate and silver chloride, are usually filtered at the laboratory temperature to avoid solubility losses. 

Crucibles fitted with permanent porous plates are cleaned by shaking out as much of the solid as possible, and then dissolving out the remainder of the solid with a suitable solvent. A hot 0.1 M solution of the tetrasodium salt of the ethylenediaminetetra-acetic acid is an excellent solvent for many of the precipitates [except metallic sulphides and hexacyanoferrates(III)] encountered in analysis. These include barium sulphate, calcium oxalate, calcium phosphate, calcium oxide, lead carbonate, lead iodate, lead oxalate, and ammonium magnesium phosphate. The crucible may either be completely immersed in the hot reagent or the latter may be drawn by suction through the crucible. 

Calcium, iron, magnesium, alkali metals, and citrates do not affect the analysis. Ammonium salts interfere and must be eliminated by means of sodium nitrite or sodium hypobromite. The hydrochloric acid normally used in the analysis may be replaced by an equivalent amount of nitric acid without any influence on the course of the reaction. Sulphuric acid leads to high and erratic results and its use should be avoided. 

Fluorimetry is generally used if there is no colorimetric method sufficiently sensitive or selective for the substance to be determined. In inorganic analysis the most frequent applications are for the determination of metal ions as fluorescent organic complexes. Many of the complexes of oxine fluoresce strongly aluminium, zinc, magnesium, and gallium are sometimes determined at low concentrations by this method. Aluminium forms fluorescent complexes with the dyestuff eriochrome blue black RC (pontachrome blue black R), whilst beryllium forms a fluorescent complex with quinizarin. 

Ammonium cerium (IV) sulphate 380 Ammonium iron (III) sulphate indicator, 354 Ammonium magnesium phosphate, thermal analysis of 498... 

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