Uses of Ammonium Sulfate

AS is a white to brownish-gray crystalline salt that is soluble in water, but is only slightly soluble in ethanol. AS has excellent storage properties in bags and in bulk, and it does not require any anti-caking conditioners. This is because AS is resistant to moisture absorption and has a critical relative humidity of 79% at 30°C244. AS can be irritating when in contact with the skin or mucous 

At atmospheric pressure, AS will decompose before it will melt. Upon decomposition it releases ammonia and leaves bisulfate behind. Above 300°C, decomposition gives N2, SO2, SOj and H2O in addition to ammonia. Its vapor pressure is effectively zero up to 80°C. 

Melamine is characterized by its three amino (-NH2) groups and by its 66.6% nitrogen content. It is known by several different names 1,3,5-triazine-2,4,6-triamine melamine crystal cyanurotriamide 2,4,6-triamino-s-triazine cyanuramide and cyanuric acid amide. Its chemical formula can be written as C3IW or C3N3(NH2)3. Liebig first prepared it in 1834, but it was not until 1937 that it was produced commercially. 

Melamine can be produced from urea, dicyandiamide (a derivative of calcium cyanide) or hydrogen cyanide. In 2001 all world production was based on urea. The dicyandiamide process was the original melamine process from the 1930 s, but it was phased out in the 1980 s. Production of melamine from hydrogen cyanide was never commercialized114. 

Melamine is produced from urea by either a high- or a low-pressure process, and either process can consist of one or two stages. The net reaction in each process is114  

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As with serum IgG (see Chapter 10), enrichment of MAbs by precipitation is a useful starting point for further purification. The use of ammonium sulfate, sodium sulfate, PEG, and caprylic acid, as described in Chapter 10, is applicable to hybridoma culture supernatants and ascitic fluid. 

It is apparent from Figure 8.6 that the use of ammonium sulfate for protein precipitation is rationalized with the salt s kosmotropic properties in addition, (NH4)2S04 is highly soluble in aqueous solution. 

The most common protein precipitation technique involves the use of ammonium sulphate, which has been the subject of a recent review (3). The widespread use of ammonium sulfate can be ascribed to the fact that it is very soluble (saturated solutions have a concentration in the region of AM), the density of solutions do not compromise collection of precipitates by centrifugation and its use does not promote denaturation of proteins. The addition of ammonium sulfate will cause a neutralization of the surface charge of the protein and a decrease in the effective concentration of water leading to a decrease in protein solvent interactions. 

In shake-flask cultures, pH control is usually limited to either addition of buffering salts such as phosphates, or periodic manual pH adjustment, which is obviously tedious and less effective. The use of ammonium sulfate as the major nitrogen source in Mandels medium (10) requires a more compelling buffering system. Without buffering, the pH drops quickly... 

In spite of the frequent use of ammonium sulfate, other hydrophobic association promoting salts can be useful at neutral pH. In that way, it is possible to select the degree of lyotropic property adapted to the antibody to purify (see Table 6). 

Much attention has been paid to metal-substituted alkaline phosphatases, notably Co" d-d spectra), Mn" (ESR) and Cd ( Cd NMR). The apoenzyme may be prepared by use of ammonium sulfate to remove zinc. After about five days the apoenzyme may be isolated having less than 3% of the original zinc. Furthermore, the apoenzyme is uncontaminated by chelating agents, which show a tendency to bind to the apoenzyme. A range of metalloalkaline phosphatases may be prepared from the apoenzyme. The binding of cadmium at three separate sites can be confirmed by the use of " Cd NMR, which shows " three separate resonances at 153, 72 and 3 p.p.m. in the phosphorylated dimer Cd"6AP. When all three sites are occupied by Cd , the enzyme has a very low turnover, at least 10 times slower than the native Zn" enzyme. This slow turnover number has made the Cd" enzyme particularly useful in NMR studies. 

The effect of the amount of melamine on the flame retardance of the resulting foams was studied in detail by Shell (131) and Dow Chemical (133). A combined use of ammonium sulfate and aluminum hydroxide was proposed by Toyo Rubber Chemical Industries Corp. (136). Recently, blends of ammonium sulfate and weakly basic organic compounds, e.g., sodium carboxylates, were patented (158, 165). 

Silica transport under hydrothermal conditions is cited to support some mechanistic postulations regarding Structure IV. Why should the explanation for the occupancy factor in Structure IV be qualitatively different than for Structure II, since Structure IV only received an intensification of the treatment given Structure II The type of hydro-thermal environment present can have an important bearing on this silica transport phenomenon. In view of your use of ammonium sulfate, did you in fact achieve the conditions for transport cited by Wyart and Sabatier Residual sulfate would be expected to be quite persistent in such a system. A further point regarding Structure IV is that we have found that the lattice parameter is a smooth function of the degree of calcination severity, so that it might be expected to be smaller than the lattice parameter for Structure III on that basis alone. 

Gray Stick indicates double grow properly. Lesser quantities of the compound are utilized in water treatment plants where it is used to control the acidity of the water being processed. Among other uses of ammonium sulfate are ... 

In a comparison of how N fertilizers that also contained S affected the elemental composition of celery (Apium graveolens) grown on polluted marsh soil, Schnug and Schnier (1986) observed that with the use of ammonium sulfate (as compared with urea or calcium ammonium nitrate) there was a conspicuous increase in total S, accompanied by a significant decrease in Mo concentration of up to 80% (Figure 15.1). In soils that are inherently poor in available Mo, or where its availability is limited by acid conditions, addition of S fertilizer may further aggravate... 

Fractional precipitation methods can have damaging effects on certain mAbs. Pilot studies can examine this possibihty. Methods classically involve the use of ammonium sulfate, sodium sulfate, caprylic acid, Rivanol, and polyethylene glycol. These separate mAh from the majority of other proteins in ascites. Following dialysis, this procedure may well be sufficient for use in ELISA. 

Another FGD method uses ammonia (NHj) as the sorbent the FGD product is ammonium sulfate [(NH4)2S04)]. Sulfate is the preferred form of sulfur readily assimilated by crops, and ammonium sulfate is the ideal sulfate compound for soil supplements because it also provides nitrogen from ammonium. The use of ammonium sulfate in large-scale fertilizer formulations has been growing gradually. This growth provides a market for FGD products and could make FGD processes based on ammonia—attractive alternatives to the processes based on lime and limestone. 

The imide can also be prepared by using of ammonium sulfate. 

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