Determination amine concentration

To determine relative amine basicity cost-effectiveness for a specific amine concentration, compare amine Kb (at the desired operating temperature and pH) to amine cost for each of various neutralizers under consideration. 

After extraction, the urethanated films were subjected to alkaline hydrolysis of urethanes to liberate the corresponding amines, while the adipoylated films were hydrolyzed after having reacted with 7-hydroxycoumarin. Amounts of the released amines and coumarin were determined by fluorescence spectroscopy as described in the Experimental section. Since aniline as well as butylamine has no appreciable fluorescence by themselves, their fluorescence assay was made after reacting with o-phthalaldehyde in the presence of mercaptoethanol. In Figure 3, where relative fluorescence intensities are plotted as a function of concentrations of amines and hydroxycoumarin, one can see that the fluorescence intensities vary linearly with their concentration to permit us the quantitative determination of extremely small amounts of amines and hydroxycoumarin. 

The sensor did not respond to volatile compounds such as acetic acid, ethyl alcohol, and amines (diethylamine, propylamine, and butylamine) or to nonvolatile nutrients such as glucose, amino acids, and metal ions (potassium and sodium ions). Therefore, the selectivity of this microbial sensor was satisfactory in the presence of these different substances. The current output of the sensor was almost constant for more than 21 days and 400 assays. The microbial sensor can be used to assay sodium nitrite for a long period. In the same experiments the concentration of sodium nitrite was determined by both the sensor proposed and the conventional method (dime-thyl-a-naphtylamine method). A good correlation was obtained between the sodium nitrite concentrations determined by the two methods (correlation coefficient 0.99). 

This proposal rests on a combination of 3 chief experimental findings. (1) The order of the reactions (5-9 ) is never less than one with respect to the concentration of the phosphazene and the amine requiring that both of these be involved in the rate-determining, or a prior, step. (2) The existence of a second-order term in the concentration of amine in non-polar solvents arising from base catalysis by amine (7). (3) The effect of the leaving group, the... 

To avoid these pitfalls two different techniques have recently been used to measure the intracellular pH in intact A. nigra blood cells97. One technique combines a measurement of the ratio of intracellular to extracellular concentration of amine with measurement of the extracellular pH to yield the intracellular pH. Another technique involves intracellular 31P-NMR (nuclear magnetic resonance) measurements. These methods led to a determination of pH7.39 0.10 for unfractionated cells, and 7.2 for the vanadocyte fraction. 

A plot of Mg vs T403 concentration, determined from the cure reactions and epoxide and amine equivalent weights, is illustrated in Figure 3 as the full line. The experimental data points in this figure were from Nielsen s ( ) empirical equation... 

CP 9002 gas chromatograph equipped with a CP-Sil-5 CB column, the sodium chloride concentrations were determined gravimetrically and the water concentrations were calculated from the determined amine and sodium chloride concentrations. 

Divalent copper, cobalt, nickel, and vanadyl ions promote chemiluminescence from the luminol—hydrogen peroxide reaction, which can be used to determine these metals to concentrations of 1—10 ppb (272,273). The light intensity is generally linear with metal concentration of 10 to 10 M range (272). Manganese(II) can also be determined when an amine is added to increase its reduction potential by stabili2ing Mn (ITT) (272). Since all of these ions are active, ion exchange must be used for deterrnination of a particular metal in mixtures (274). 

Ammonia.. The most rehable results for ammonia are obtained from fresh samples. Storage of acidified samples at 4°C is the best way to minimi2e losses if prompt analysis is impossible. The sample acidity is neutrali2ed prior to analysis. Ammonia concentrations of 10 -0.5 M can be determined potentiometricaHy with the gas-sensing, ion-selective electrode. Volatile amines are the only known interferents. 

Although pH determines the ratio of hypohalous acid to hypohaUte ion, the fraction of the total available halogen present as HOX is dependent on of the halamine as well as the concentration of excess amine. In the case of chloroisocyanurates, which are the most widely used /V-ch1oramine disinfectants in swimming pools and spas, the extent of hydrolysis at 1 ppm av CI2 (as monochloroisocyanurate) is - 34% but only - 1% when 25 ppm cyanuric acid is added (4). Nevertheless, effective disinfection can stiU occur with chloroisocyanurates if a sufficient FAC is maintained, eg, 1—3 ppm. The observed reduction in disinfection rate because of cyanuric acid (6) has been shown to be direcdy related to the concentration of HOCl formed by hydrolysis of chloroisocyanurates (10). 

The circulation rates for amine systems can be determined from the acid gas flow rates by selecting a solution concentration and an acid gas loading. 

The initial anhydride concentration was about 3 x 10 M, and the amine concentration was much larger than this. The reaction was followed spectrophoto-metrically, and good first-order kinetics were observed hence, the reaction is first-order with respect to cinnamic anhydride. It was not convenient analytically to use the isolation technique to determine the order with respect to allylamine, because it is easier to observe the cinnamoyl group spectrophotometrically than to follow the loss of amine. Therefore, the preceding experiment was repeated at several amine concentrations, and from the first-order plots the pseudo-first-order rate constants were determined. These data are shown in Table 2-1. Letting A represent... 

The differenee in reaction rates of the amino alcohols to isobutyraldehyde and the secondary amine in strong acidic solutions is determined by the reactivity as well as the concentration of the intermediate zwitterions [Fig. 2, Eq. (10)]. Since several of the equilibrium constants of the foregoing reactions are unknown, an estimate of the relative concentrations of these dipolar species is difficult. As far as the reactivity is concerned, the rate of decomposition is expected to be higher, according as the basicity of the secondary amines is lower, since the necessary driving force to expel the amine will increase with increasing basicity of the secondary amine. The kinetics and mechanism of the hydrolysis of enamines demonstrate that not only resonance in the starting material is an important factor [e.g., if... 

The analytical capability of these matrices has been demonstrated for chiral amines [12, 13]. The procedure is illustrated in Fig. 8-4 for the separation of NapEtNH " CIO . Concentrated methanol/dichloromethane solutions of the racemic mixture were placed on a column containing the chiral macrocycle host. The enantiomers of the ammonium salts were resolved chromatographically with mixtures of methanol and dichloromethane as the mobile phase. The amounts of R and S salts in each fraction were determined by polarimetry. Because the chiral supported macrocycle interacts more strongly with S salts, the R salt passes through the column first and the S salt last, as seen in Fig. 8-4. 

Procedure. To obtain experience in the method, the purity of analytical-grade potassium chlorate may be determined. Prepare a 0.02M potassium chlorate solution. Into a 250 mL conical flask, place 25.0 mL of the potassium chlorate solution, 25.0mL of 0.2M ammonium iron(II) sulphate solution in 2M sulphuric acid and add cautiously 12 mL concentrated sulphuric acid. Heat the mixture to boiling (in order to ensure completion of the reduction), and cool to room temperature by placing the flask in running tap water. Add 20 mL 1 1 water/phosphoric(V) acid, followed by 0.5 mL sodium diphenyl-amine-sulphonate indicator. Titrate the excess Fe2+ ion with standard 0.02M potassium dichromate to a first tinge of purple coloration which remains on stirring. 

A. Diazotisation method Discussion. In this procedure the amine is diazotised and then coupled with N-(1 -naphthyl)ethylenediamine. This leads to formation of a coloured product whose concentration can be determined with an absorptiometer or a spectrophotometer. 

Discussion. The formation of coloured compounds by coupling phenols with diazotised primary aromatic amines has long been recognised as a method of determining phenols, and procedures have been evolved whereby the phenol solution is titrated with a diazonium solution which has been calibrated against known concentrations of the phenol. The resultant reaction products are coloured, but many are only sparingly soluble in water and organic solvents and do not therefore lend themselves to colorimetric determination. 

Square brackets in kinetic equations signify the effective concentrations of the bracketed species, these being the equilibrium forms actually taking part in the rate-determining step. Parentheses are used for stoichiometric concentrations. Thus (ArNH2) is the total amount of an amine present in the system, even if it... 

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