Ammonium Acetate Sulphate

Discussion. Some of the details of this method have already been given in Section 11.11(C), This procedure separates aluminium from beryllium, the alkaline earths, magnesium, and phosphate. For the gravimetric determination a 2 per cent or 5 per cent solution of oxine in 2M acetic add may be used 1 mL of the latter solution is suffident to predpitate 3 mg of aluminium. For practice in this determination, use about 0.40 g, accurately weighed, of aluminium ammonium sulphate. Dissolve it in 100 mL of water, heat to 70-80 °C, add the appropriate volume of the oxine reagent, and (if a precipitate has not already formed) slowly introduce 2M ammonium acetate solution until a precipitate just appears, heat to boiling, and then add 25 mL of 2M ammonium acetate solution dropwise and with constant stirring (to ensure complete predpitation). 

Materials Required Acetomenaphthone 0.2 g glacial acetic acid 15 ml dilute hydrochloric acid (10% w/v) 15 ml ammonium ceric sulphate 0.05 N ferroin sulphate solution. 

Procedure Weigh accurately about 0.2 g of acetomenaphthone and boil it with 15 ml of glacial acetic acid and 15 ml of dilute hydrochloric acid under a reflux condenser for 15 minutes. Cool the contents carefully and taking adequate precautions to avoid any atmospheric oxidation. Add 0.1 ml of ferroin sulphate solution as indicator and titrate with 0.05 N ammonium ceric sulphate. Repeat the assay without the substance being examined (blank determination) and incorporate the correction, if any. Each ml of 0.05 N ammonium ceric sulphate is equivalent to 0.006457 g of C15H1404. 

Tocopherol acetate 0.3 g Diphenyl amine Each ml of 0.1 N ammonium ceric sulphate = 0.002364 g of C31H5203... 

Procedure Weigh accurately 0.20 g of glycobiarsol into a 250-ml conical flask and add 10.0 ml of 0.05 M disodium edetate. Warm the contents of the flask over a water-bath until glycobiarsol gets dissolved completely and then cool the contents to the room temperature (25°C). Add to it 10.0 ml of acetic acid-ammonium acetate buffer, 25.00 ml of alcohol and 2 ml of dithizone solution as an indicator. Titrate the excess of disodium edetate with 0.025 M zinc sulphate until the resulting solution turns rose pink in colour. Each millilitre of 0.05 M disodium edetate consumed is equivalent to 10.45 mg of Bi. 

Materials Required Ammonium nickel sulphate (pure) 0.0135 g phthalate or acetate (ethanoate) buffer (pH 6.0) 5 ml dilute ammonia solution chloroform 15 ml sodium hydroxide (0.1 M) 10.0 ml ... 

Another study employed an ODS column and different mobile phase composition for the measurement of carotenoids in orange juice. Citrus fruits were hand-squeezed and the juice was filtered. Aliquots of 5 ml of juice were extracted with ethyl acetate (3 X 50 ml) containing 0.004 per cent butyl hydroxytoluene (BHT). The organic phase was dried with 50 g of anhydrous sodium sulphate and the aqueous phase was mixed with 50 ml of mehanol and 100 ml of 1 M NaCl, extracted with 75 and 25 ml of ethyl acetate. The ethyl acetate fractions were combined, evaporated to dryness at 40°C and redissolved in the mobile phase. Extracts were analysed in an ODS column (250 X 4.6 mm i.d. particle size 5 jian). The mobile phase consisted of ACN-methanol-l,2-dichloroethane (60 35 5, v/v) containing 0.1 per cent BHT, 0.1 per cent triethylamine and 0.05 M of ammonium acetate. The column was not thermostated and the flow rate was 1 ml/min. Pigments were detected... 

Various liquid chromatographic techniques have been frequently employed for the purification of commercial dyes for theoretical studies or for the exact determination of their toxicity and environmental pollution capacity. Thus, several sulphonated azo dyes were purified by using reversed-phase preparative HPLC. The chemical strctures, colour index names and numbers, and molecular masses of the sulphonated azo dyes included in the experiments are listed in Fig. 3.114. In order to determine the non-sulphonated azo dyes impurities, commercial dye samples were extracted with hexane, chloroform and ethyl acetate. Colourization of the organic phase indicated impurities. TLC carried out on silica and ODS stationary phases was also applied to control impurities. Mobile phases were composed of methanol, chloroform, acetone, ACN, 2-propanol, water and 0.1 M sodium sulphate depending on the type of stationary phase. Two ODS columns were employed for the analytical separation of dyes. The parameters of the columns were 150 X 3.9 mm i.d. particle size 4 /jm and 250 X 4.6 mm i.d. particle size 5 //m. Mobile phases consisted of methanol and 0.05 M aqueous ammonium acetate in various volume ratios. The flow rate was 0.9 ml/min and dyes were detected at 254 nm. Preparative separations were carried out in an ODS column (250 X 21.2 mm i.d.) using a flow rate of 13.5 ml/min. The composition of the mobile phases employed for the analytical and preparative separation of dyes is compiled in Table 3.33. 

Sulphates. — On adding 1 cc. of hydrochloric acid to a solution of 1 gm. of ammonium acetate in 20 cc. of water, followed by barium chloride solution, no precipitate of barium sulphate should form on standing twelve hours. 

It is rarely necessary to determine quantitatively the separate components of the residue. When the lead sulphate is to be determined, the residue is extracted with ammonium acetate solution in the hot, the liquid filtered and the filtrate precipitated with hydrogen sulphide the lead sulphide is dissolved in nitric acid, and the procedure indicated in the next section (6) followed. 

The part insoluble in dilute acid is digested in the cold with 50 c.c. of ammonium acetate solution (D 1-04), this dissolving the lead sulphate, which may be estimated by evaporating to dryness the filtrate and calcining the residue with a little sulphuric acid. 

The part insoluble in ammonium acetate, containing the lead chromate, barium sulphate and clay, is suspended in 50 c.c. of water, treated with 25 c.c. of caustic potash solution (112 grams per litre) and heated to boiling for 10 minutes the lead chromate dissolves, whilst the barium sulphate and clay or kaolin remain undissolved and are collected, calcined and weighed. 

Lead sulphate precipitate is soluble in more concentrated solutions of ammonium acetate (10m) (a) or ammonium tartrate (6m) (b) in the presence of ammonia, when tetraacetateplumbate(II) and ditartratoplumbate(II) ions are formed ... 

Dilute sulphuric acid heavy, white, finely divided precipitate of barium sulphate BaS04, practically insoluble in water (2 5 mg -1 Ks = 9 2 x 10 1 ), almost insoluble in dilute acids and in ammonium sulphate solution, and appreciably soluble in boiling concentrated sulphuric acid. By precipitation in boiling solution or preferably in the presence of ammonium acetate, a more readily filterable form is obtained. 

Lead acetate solution white precipitate of lead sulphate, PbS04, soluble in hot concentrated sulphuric acid, in solutions of ammonium acetate and of ammonium tartrate (see under Lead, Section III.4, reaction 5), and in sodium hydroxide solution. In the last case sodium tetrahydroxoplumbate(II) is formed, and on acidification with hydrochloric acid, the lead crystallizes out as the chloride. If any of the aqueous solutions of the precipitate are acidified with acetic acid and potassium chromate solution added, yellow lead chromate is precipitated (see under Lead, Section III.4, reaction 6). 

Fluoride, hexafiuorosilicate, and sulphate in the presence of each other The following differences in solubilities of the lead salts are utilized in this separation lead hexafiuorosilicate is soluble in water lead fluoride is insoluble in water but soluble in dilute acetic acid lead sulphate is insoluble in water and in boiling dilute acetic acid, but soluble in concentrated ammonium acetate solution. 

Wash well with cold water. Divide into two parts. (i) Smaller portion. Add excess dilute acetic acid and boil (this will dissolve any lead fluoride). White residue indicates sulphate. The residue is soluble in ammonium acetate solution. (ii) Larger portion. Treat cautiously with concentrated sulphuric acid and test with a moist glass rod. Milkiness of the water and etching of the tube indicate fluoride. Add Ba(N02)2 solution and warm gently. White crystalline precipitate indicates hexafluoro-silicate. 

Upon warming the solution, the hydrogen halides are expelled from solution with effervescence. When the solution is diluted, the complex di-iodoargentate is decomposed and silver iodide is precipitated it is best, however, to expel the excess of hydriodic acid by evaporation before diluting with water. If lead sulphate was originally present, lead iodide will be precipitated on dilution this can be separated from silver iodide by extraction with ammonium acetate solution. 

The objection to the use of S02 is that some sulphuric acid may be formed, especially upon boiling, and this may partially precipitate Pb, Sr, and Ba as sulphates. Any precipitate formed in this process should accordingly be examined for these cations PbS04 is soluble in ammonium acetate solution. 

Sulphate, (i) BaCl2 solution and dilute HC1 test, and reduction to sulphide test for latter with sodium nitroprusside or lead acetate solution (IV.24, 1). (ii) Lead acetate test and solubility of PbS04 in ammonium acetate solution (IV.24, 2). 

The lead acetate test on the solution and the dissolution of the resulting precipitate of lead sulphate in ammonium acetate solution are also characteristic (IV.24, 2). 

Sodium phosphate solution white precipitate of uranyl phosphate U02HP04, soluble in mineral acids but insoluble in dilute acetic acid. If precipitation is effected in the presence of ammonium sulphate or of ammonium acetate, uranyl ammonium phosphate, U02(NH4)P04 is precipitated. 

There are several salts that behave in this way at atmospheric temperatures, the more important being ammonium acetate potassium bromate, carbonate, cyanide, ferricyanide, ferrocyanide, iodate, and permanganate disodium hydrogen phosphate and sodium borate and carbonate.4 In the case of potassium chlorate the points L and S appear to be practically coincident, whilst for the majority of salts the point S lies somewhere to the left of L, namely at S —that is to say, saturation occurs before the limiting concentration is reached. Generally speaking, at the ordinary temperature, concentrated solutions of salts are less corrosive than distilled water—that is, the point S lies below the level of A, exceptions being 5 ammonium sulphate, aluminium... 

Felix et al. (1960) and Sulkowski and Laskowski (1962) used the solvents ethanol M ammonium acetate (75 30, v/v) and saturated ammonium sulphate isopropanol water (80 2 18, v/v/v) in two dimensions. This provides high resolution of small ribo- and deoxy-ribo-oligonucleotides. The method distinguishes between Ap and Cp residues. 

Weigh 0.1 g of resorcinol into a clean dry beaker and dissolve in 0.5 ml of glacial acetic acid. Add 5 ml of the test solution, mix and add 0.1 g of ammonium ferrous sulphate. Prepare a blank test solution for comparison. A green colour in the test sample, compared with a pale yellow in the blank indicates the presence of nitrogen. 

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