Ammonia analytical determination

Study of kinetic and storage properties of the immobilized enzyme continuous conversion of L-asparagine to L-aspartate and ammonia analytical determination of L-asparaginase levels in dogs before and after treatment and using an extracorporeal shunt Batch production of a-amylase by the living inunobilized cells Removal of soluble enzymes, prederivatized with an arylsulphonamide, from reaction solutions... 

The analytical phase generally involves the use of very dilute solutions and a relatively high ratio of oxidant to substrate. Solutions of a concentration of 0.01 M to 0.001 M (in periodate ion) should be employed in an excess of two to three hundred percent (of oxidant) over the expected consumption, in order to elicit a valid value for the selective oxidation. This value can best be determined by timed measurements of the oxidant consumption, followed by the construction of a rate curve as previously described. If extensive overoxidation occurs, measures should be taken to minimize it, in order that the break in the curve may be recognized, and, thence, the true consumption of oxidant. After the reaction has, as far as possible, been brought under control, the analytical determination of certain simple reaction-products (such as total acid, formaldehyde, carbon dioxide, and ammonia) often aids in revealing what the reacting structures actually were. When possible, these values should be determined at timed intervals and be plotted as a rate curve. A very useful tool in this type of investigation, particularly when applied to carbohydrates, has been the polarimeter. With such preliminary information at hand, a structure can often be proposed, or the best conditions for a synthetic operation can be outlined. 

The amount of standardized acid needed is proportional to the amount of ammonia that bubbled through. It is an indirect method because the ammonia is determined but not titrated. It is determined indirectly by titration of H2B03. In a direct titration, the analyte would be reacted directly with the titrant, as per the discussion in Section 4.6. The concentration of the boric acid in the receiving vessel does not enter into the calculation and need not be known. Equation (4.40) is used for the calculation. 

In the analytical determination of the hyponitrites, W. Zorn treated soln. of the free acid, or of its salts in cold dil. nitric acid with an excess of silver nitrate, and just neutralized the free acid with ammonia or sodium carbonate. The washed and dried precipitate was weighed as silver hyponitrite, or weighed as metal or chloride. A. Thum treated the aq. soln. of the acid with an excess of a soln. of permanganate, and in 15 minutes added sulphuric acid after standing for another hour the soln. was warmed to 30°, and treated with a known quantity of 0-1A-oxalie acid sufficient to decolorize the permanganate. The excess oxalic acid was determined by permanganate titration. A. Hantzsch and A. Sauer, and... 

Ion-selective electrodes can be used for analytical determinations over an extremely wide range of solution concentrations (from 10" to 10 M to saturation) and are therefore applicable to trace as well as to major-constituent analysis. There are presently about two dozen ion-selective electrodes commercially available for cations, including the heavy metals for anions such as fluoride, sulfide, and the halides and for gases such as oxygen, carbon dioxide, and ammonia. ... 

Analytical Procedures. Standard methods for analysis of food-grade adipic acid are described ia the Food Chemicals Codex (see Refs, ia Table 8). Classical methods are used for assay (titration), trace metals (As, heavy metals as Pb), and total ash. Water is determined by Kad-Fisher titration of a methanol solution of the acid. Determination of color ia methanol solution (APHA, Hazen equivalent, max. 10), as well as iron and other metals, are also described elsewhere (175). Other analyses frequendy are required for resia-grade acid. For example, hydrolyzable nitrogen (NH, amides, nitriles, etc) is determined by distillation of ammonia from an alkaline solution. Reducible nitrogen (nitrates and nitroorganics) may then be determined by adding DeVarda s alloy and continuing the distillation. Hydrocarbon oil contaminants may be determined by ir analysis of halocarbon extracts of alkaline solutions of the acid. 

For the increase of sensitiveness of the voltamperometric determination Co(II) use o,o -dihydroxysubstituted azodyes (eriochrome red B and calces). The Co(II) determination can be conducted at potential of reduction of coordinating connection of Co(II)-azodye (E = - 0,9V) and directly the Co(II) (E = -1,2V, ammonia buffer solution) ions. The results of reseaixhes show that selectivity of the Co(II) determination in presence the Ni(II) and Pd(II) ions more high with the use of analytical signal at the potential -1,2V. Is it thus succeeded move aside potentials of peaks of reduction of the Ni(II) and Co(II) ions on a background ammoniac buffer solution from AE=0,2V to AE = 0,4-0,5V. The Co(II) determination can be conducted in presence 50-100 multiple surpluses Ni(II). Palladium in these conditions does not prevent to 60 multiple surplus. 

Tellurium nitride was first obtained by the reaction of TeBt4 with liquid ammonia more than 100 years ago. The empirical formula TeN was assigned to this yellow, highly insoluble and explosive substance. However, subsequent analytical data indicated the composition is Tc3N4 which, in contrast to 5.6a and 5.6b, would involve tetravalent tellurium. This conclusion is supported by the recent preparation and structural determination of Te6N8(TeCl4)4 from tellurium tetrachloride and tris(trimethylsilyl)amine (Eq. 5.5). The TceNs molecule (5.12), which is a dimer of Tc3N4, forms a rhombic dodecahedron in which the... 

Wheat samples are extracted with dilute ammonia on the ASE200. The extracts are amended with isotopically labeled internal standards. The extracts are purified by sequential octadecyl reversed-phase solid-phase extraction (Cig SPE) and ethylenediamine-iV-propyl anion exchange (PSA) SPE. The samples are analyzed by LC/MS/MS. This method determines crop residues of flucarbazone-sodium and A-desmethyl flucarbazone with a limit of quantitation (LOQ) of 0.01 mgkg for each analyte. 

In order to suppress interferences due to the presence of inorganic species and reliably determine the proteinaceous composition of the sample, a clean-up step has often been introduced in the analytical procedure. This step may include the extraction of the proteinaceous matter by an ammonia solution [8], the use of a cation-exchange resin [8,55], a chelating agent [9,41,44], the use of a Cig resin or the use of barium chloride solution to suppress sulfates [10,81,82]. Table 9.1 reports the methods used to overcome such problems. 

The determination of ammonia in non-saline waters does not present any analytical problems and, as seen above, reliable methods are now available for the determination of ammonia in seawaters. In the case of estuarine waters, however, new problems present themselves. This is because the chloride content of such waters can vary over a wide range from almost nil in rivers entering the estuary to about 18 g/1 in the edges of the estuary where the water is virtually pure seawater. 

Soil samples were collected along a traverse over the Honerat kimberlite and extended off the kimberlite approximately 75 m SE and 225 m NW from the pipe s centre (Fig. 1). Although it is common practice to collect samples from upper B-horizon soil (Levinson 1980 Bajc 1998 Mann et al. 2005) our samples were collected from C-horizon soil because GAGI samplers were placed at a depth of 60 cm (well below the B horizon). Within 8 hours of sampling, a portion of each soil sample was mixed with Milli-Q water (1 1) to create a slurry. The values of pH and oxidation-reduction potential (ORP) were determined in each slurry. Ammonia acetate leach of the soil samples were performed at Acme Analytical Laboratories, Vancouver, where 20 ml of ammonium acetate was mixed with 1 g soil sample and elements were determined by inductively coupled plasma-mass spectrometry. The GAGI samplers installed at Unknown were placed in piezometers and submerged in water at a depth of approximately 1 m below ground surface. 

Cyanide metabolizes in the human body to thiocyanate, and its biodegradation products include ammonia, carbon dioxide, nitrate, or nitrogen (Richards and Shieh 1989). The detection of thiocyanate in body fluids may indicate cyanide exposure. Similarly, the amounts of cyanide degradation products formed in an environmental medium could be used to measure cyanide s biodegradation rate. A summary of methods for determining environmental degradation products is shown in Table 6-4. Suitable analytical methods are available to detect all of these compounds (Pettigrew and Fell 1973 Richards and Shieh 1989). 

Reflectance measurements provided an excellent means for building an ammonium ion sensor involving immobilization of a colorimetric acid-base indicator in the flow-cell depicted schematically in Fig. 3.38.C. The cell was furnished with a microporous PTFE membrane supported on the inner surface of the light window. The detection limit achieved was found to depend on the constant of the immobilized acid-base indicator used it was lO M for /7-Xylenol Blue (pAT, = 2.0). The response time was related to the ammonium ion concentration and ranged from 1 to 60 min. The sensor remained stable for over 6 months and was used to determine the analyte in real samples consisting of purified waste water, which was taken from a tank where the water was collected for release into the mimicipal waste water treatment plant. Since no significant interference fi-om acid compounds such as carbon dioxide or acetic acid was encountered, the sensor proved to be applicable to real samples after pH adjustment. The ammonium concentrations provided by the sensor were consistent with those obtained by ion chromatography, a spectrophotometric assay and an ammonia-selective electrode [269]. 

Alegret et al. devised a pH ISFET based on a flow-through cell designed by themselves and an FI manifold including a gas-diffusion module for the on-line separation of gaseous analytes with acid-base properties. In this way, they obtained a linear determination range of 1 x 10 -1 x 10 M for ammonia and 7 x 10" -4 x 10 M for sulphur dioxide, with an RSD of 1% and 0.5%, respectively [153]. 

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