Magnesium acetate, solution preparation

A solution of 85.8 g (0.2 moles) of 3/ -acetoxy-27-norchoIest-5-en-25-one in 500 ml of anhydrous thiophen-free benzene is added to a Grignard solution prepared from 24.3 g (1 g-atom) of magnesium and 149 g (1.05 moles) of freshly distilled methyl iodide in 575 ml of anhydrous ether. The mixture is refluxed for 3 hr and allowed to stand overnight. After cooling to 5° the complex is decomposed by the slow addition of 200 ml of ice water and 400 ml of 50% acetic acid solution, and steam distilled until no more oil passes over. The residual product is filtered, washed with water and dried at 80°. Crystallization from methanol gives 70 g (87%) of cholest-5-ene-3)5,25-diol mp 179.5-181°. The analytical sample melts at 181.5-182.5° [a]o —39° (CHCI3). 

These aspects of solvent property similarly apply to precoated impregnated silica gel plates, e.g., by ammonium sulfate, silver nitrate, or magnesium acetate, as well as to microcrystalline cellulose precoated plates. On preparative RP phases, water has the lowest elution power. Therefore, more polar or aqueous solvents should be preferred. In contrast to HPTLC RP-18 layers, on which such aqueous solutions remain as a drop on the surface and are not able to penetrate through the lipophilic layer, on preparative RP phases, pnre aqneons application solutions can be apphed owing to the minor degree of C18 modification. 

The following substance, namely magnesium acetate potassium citrate potassium hydroxide potassium nitrate and sodium chloride can also be assayed for their respective elements as shown in Table 25.1 below. However, all the respective solutions of the said pharmaceutical substance and their standard solutions must be prepared as prescribed in BP (1993) strictly to obtain the best results. 

Magnesium-Chelating Substances Transfer 1 g of sample, accurately weighed, into a small beaker, and dissolve it in 5 mL of water. Add 5 mL of a buffer solution prepared by dissolving 67.5 g of ammonium chloride in 200 mL of water, adding 570 mL of ammonium hydroxide, and diluting with water to 1000 mL. Then add 5 drops of eriochrome black TS to the buffered solution, and titrate with 0.1 M magnesium acetate to the appearance of a deep wine red color. Not more than 2.0 mL is required. 

The reagent is prepared as follows. Dissolve 10 g uranyl acetate in 6g glacial acetic acid and 100 ml water (solution a). Dissolve 33 g magnesium acetate in 10 g acetic acid and 100 ml water (solution b). Mix the two solutions a and b, allow to Stand for 24 hours, and filter. Alternatively, a reagent of equivalent concentration may be prepared by dissolving uranyl magnesium acetate in the appropriate volume of water or of m acetic acid. 

Procedure Prepare two solutions, a sodium azide solution, and a lead-II-acetate solution by dissolving 8.3 grams of sodium azide into 71 milliliters of water, and dissolve 21 grams of lead-II-acetate into 179 milliliters of water. Then quickly place each solution into a freezer and chill to about 5 Celsius. Thereafter, place the sodium azide into an ice bath, and then rapidly add the lead-II-acetate solution. Upon mixing, the LZ will instantaneously precipitate. After mixing both solutions, carefully filter-off the precipitated product, carefully wash with 100-milliliters of ice-cold water, and then dry in a desiccator filled with anhydrous magnesium sulfate. Do not vacuum dry or air-dry. The dry product should never be kept dry. For storage, keep the dry LZ suspended in a water free solvent such as kerosene. The product can be stored wet with water for short periods of time. 

Heavy metals <1.07> To 1.0 g of magnesium silicate add 20 mL of water and 3 mL of hydrochloric acid and boil for 2 min. Filter, and wash the residue on the filter with two 5 mL portions of water. Evaporate the combined filtrate and washings on a water bath to dryness, add 2 mL of dilute acetic acid to the residue, warm imtil solution is complete, filter, if necessary, add water to make 50 mL, and perform the test using this solution as the test solution. Prepare the control solution with 3.0 mL of standard lead solution, 2 mL of dilute acetic acid and water to make 50 mL (not more than 30 ppm). 

Where atomic absorption spectrophotometry is possible the ammonium acetate extract can be directly analysed for Ca and Mg. The spectrophotometric standards are prepared in the ammonium acetate solution and both the standard and extracts are read against ammonium acetate as blank. If AAS is not possible the calcium and magnesium are analysed by complexometric titrations using ethylene diamine tetra acetic acid (EDTA). 

Preparation of pellet thaw the pellet in 37°C water. To the lysate, add 4 mL/g wet weight of 20 mM Tris-HCl, 40 mM magnesium acetate, 0.5% Triton X-100, pH 7.4 Add 30 U/g of DNase I and incubate for 30 min at ambient temperature with shaking Place a plastic pipet tip in the solution, cap, and sonicate 20 min in a bath sonicator (e g, Branson 1200) (see Note 2). Centrifuge this reduced viscosity sample at 15,000g for 45 min. The resulting supernatant contains CRABPI... 

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