DETERMINATION OF MAGNESIUM

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. 

Concentration limits of the diphosphate-ion, admissible to determination of magnesium and cobalt, manganese and cobalt, zinc and cobalt by spectrophotometric method with application of the l-(2-pyridylazo)-resorcinol (PAR) are presented. Exceeding maintenance of the diphosphate-ion higher admissible supposes a preliminary its separation on the anionite in the H+-form. The optimum conditions of cobalt determination and amount of the PAR, necessary for its full fastening are established on foundation of dependence of optical density of the cobalt complex with PAR from concentration Co + and pH (buffer solutions citrate-ammoniac and acetate-ammoniac). 

The reaction mixture was stirred at reflux for an additional 30 minutes when nearly all of the magnesium had dissolved and determination of magnesium in an aliquot of the solution showed that an 82% yield of Grignard reagent had been obtained. The reaction mixture was cooled in an ice bath and stirred while 24.67 g (0.1 mol) of 2-chlorothiaxanthone was added over a period of 10 minutes. The reaction was stirred at room temperature for 30 minutes then allowed to stand overnight in the refrigerator. The tetrahydrofuran was evaporated at 50°C under reduced pressure. Benzene, 150 ml, was added to the residue. 

DETERMINATION OF MAGNESIUM. MANGANESE AND ZINC IN A MIXTURE USE OF FLUORIDE ION AS A DEMASKING AGENT... 

Two methods are commonly used for the determination of magnesium. Titan yellow may be used to obtain a coloured colloidal suspension, or solochrome black to give a red soluble complex. In most cases the second of these is to be preferred. 

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. 

Schall192) recommended that the atomic absorption determination of magnesium, calcium, manganese, iron, and copper in fertilizers should be adopted as official, first action. 

The automated determination of magnesium in urine using o.o -dihyroxyazobenzene (DAB). The final reagent concentrations obtained are ... 

Working curve for the determination of magnesium with molybdenum as internal standard. 

Spiers, C. II. Note on the volumetric determination of magnesium sulphate... 

B.3 Operation and Optimization of an Atomic Absorption Spectrometer and Determination of Magnesium in Synthetic Human Urine. 

Official methods have been published for the determination of exchangeable and extractable magnesium in soils [131]. Magnesium is extracted from the soil with 1M ammonium acetate and determined by atomic absorption spectrometry. The determination of magnesium in soils is also discussed under Multi-Metal Analysis of Soils in Sects. 2.55 (atomic absorption spectrometry), 2.55 (inductively coupled plasma atomic emission spectrometry), 2.55 (photon activation analysis) and 2.55 (ion chromatography). 

An official method has been published for the determination of magnesium in plant material [27]. A hydrochloric acid digest of the sample is treated with strontium chloride perchloric acid releasing agent and magnesium is determined by AAS using the 285 nm emission line. See Sect. 7.34.1. 

The determination of magnesium is so sensitive that there is rarely any reason for attempting to determine the element by AFS or AES. Nevertheless, the element may be determined with good sensitivity at 285.2 nm by AES using a nitrous oxide-acetylene flame, although potassium should then be added as an ionization buffer, especially at very low magnesium concentrations. 

This is by far the most frequently encountered interference in AAS. Basically, a chemical interference can be defined as anything that prevents or suppresses the formation of ground state atoms in the flame. A common example is the interference produced by aluminium, silicon and phosphorus in the determination of magnesium, calcium, strontium, barium and many other metals. This is due to the formation of aluminates, silicates and phosphates which, in many instances, are refractory in the analytical flame being used. 

In slower production processes, atomic absorption can be used directly for production control of those processes for which rapid sample preparation techniques have been developed. One such example is the determination of magnesium concentration during the production of cast iron [70]. A further example is the determination of acid soluble aluminium in steel [147], where in large steel companies 100 samples or more per day may be required. (See also section II.A.)... 

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