Ammonia measurement

Note that the 14 ppm of ammonia measured in the accumulated condensate may not accurately reflect the potentially higher level of ammonia dissolved in a thin film of moisture that could form on the metal wall in the region of initial condensation. This film of water could be saturated witb ammonia, increasing susceptibility of the metal to SCC. 

This is a significant and simple result. Thirty milliliters of hydrogen chloride combine with just 30 ml of ammonia, measured at the same temperature and pressure. Therefore, one liter of hydrogen chloride would combine with just one liter of ammonia. Though a given volume of ammonia weighs less than the same volume of... 

Langford, A. O., P. D. Goldan, and F. C. Fehsenfeld, A Molybdenum Oxide Annular Denuder System for Gas Phase Ambient Ammonia Measurements, J. Atmos. Chem., 8, 359-376 (1989). 

Ishida H, Satou T, Tsuji K et al (2008) The breath ammonia measurement of the hemodialysis with a QCM-NH3 sensor. Biomed Mater Eng 18(2) 99-106... 

Experiment 3. Rates of Formation of Ethylenediamine and Ammonia vs. Rate of Disappearance of Cobalt (II). Carbon dioxide-free air was bubbled through the solution. Ammonia, ethylenediamine, and cobalt (II) were determined periodically over a total reaction time of 5 hours. The results of this experiment are collected in Table I and plotted in Figure 3. The ammonia measured was actually the ammonia volatilized during the reaction, but it was calculated as moles per liter of solution in order to be consistent with the ethylenediamine and cobalt (II) results. 

The series of investigations carried out at the L. Ya. Karpov Physicochemical Institute by A. I. Shatenshtein, V. A. Pleskov, A. M. Monoszon, and others has been concerned with the properties of acid-base equilibria in liquid ammonia. Measurements have been made of the kinetics of ammonolysis catalysed by acids (Shatenshtein... 

Light—absorbing impurities the absorbance of a 5% solution of silver sulfadiazine in 35% ammonia, measured at 400 nm, may not exceed 0.20. This demand seems to be sharp because Indemans (14) reported for three batches an absorbance between 0.199 and 0.273, while the three batches meet the other requirements. 

The substrate specificities of all four biochemically characterized fungal nitrilases and two enzymes from rhodococci (an aromatic and an aUphatic nitrilase) are compared in Table 14.3. Only a few nitriles were examined as substrates of aU these enzymes. Moreover, the comparison of substrate specificity is difficult in some cases as different activity assays have been used for different enzymes. For instance, the determination of activity by ammonia measurement did not reflect potential amide formation. Nevertheless, common patterns can be found in substrate preferences of aromatic nitrilases. 

Recently, however, a correlation has been found between the pH-dependent (gaseous) partial pressure of the arterial NH3 and the clinical degree of HE. (54) A recent study showed that ammonia levels (arterial and venous) as well as arterial and venous partial pressure of ammonia correlate with the severity of HE. It was hereby demonstrated that venous sampling is adequate for ammonia measurement. (75) Another study suggests there is no significant difference between arterial and venous ammonia levels or partial pressure of ammonia no correlation of these three ammonia values with HE was found. (71)... 

Figure 4 Activation of energy of desorption of ammonia measured by TPD as a function of coverage for a series of H-Y zeoiites with different iattice aiuminum content O HjoNasAise-Y H3,tte2Ai4o-Y A Hj NaAias-Y."...

Both enzymatic and chemical methods are used to measure ammonia in body Buids. Enzymatic assay with glutamate dehydrogenase is the most frequently used method. Plasma ammonia measurement is particularly susceptible to contamination, leading to falsely elevated concentrations. Some of the common samphng problems are discussed in the third edition of this textbook. 

Moderate Reduce the hazards of a process by handling materials in a less hazardous form, or under less hazardous conditions, for example at lower temperatures and pressures. Dilution is one of the key words. Aqueous ammonia should be used instead of anhydrous NH3. Aqueous HCl in place of anhydrous HCl. Sulfuric acid in place of oleum. Figure 1.15 shows an example of the relevant effects observed for the concentration of ammonia measured in air as a function of distance from the place of rupture of a tank containing anhydrous or diluted ammonia solution. Less severe processing conditions are also another keyword. The use of improved catalysts is a critical element in reaching this objective and will be discussed extensively in the following chapters. 

Figure 1.15 Concentration of ammonia measured in air as a function of the distance from the place of the rupture of a tank containing anhydrous or diluted ammonia solution.

Baum MM, Kiyomiya ES, Kumar S, et al. 2001. Multicomponent remote sensing of vehicle exhaust by dispersive absorption spectroscopy. 2. Direct on road ammonia measurements. Environ Sci Technol 35(18) 3735-3741. 

Harward CN, McClenny WA, Hoell JM, et al. 1982. Ambient ammonia measurements in coastal Southeastern Virginia. Atmos Environ 16(10) 2497-2500. 

Following synthesis, urea is transported in the bloodstream to the kidneys, which filter it for excretion. Measurements of blood urea nitrogen (BUN) levels provide a sensitive clinical test of kidney function, because filtration and removal of urea are impaired in cases of kidney malfunction. Analogously, blood ammonia measurements are a sensitive test of liver function. 

Figure 23 further shows that after changing the flow to NHs/He, [ N]-NH3 desorbs and travels as a pulse through the reactor. This indicates that [13N]-NH3 exchanges rapidly with [ Nj-NHs. At first sight, this exchange process is very similar to the experiment shown in Figure 22. However, in this case, radio-labelled ammonia is not in full equilibrium on 7-almnina. After switching to imlabelled ammonia, first of all, the available Lewis sites are saturated. The time to satmate the 7-alumina bed with ammonia, measured with the mass spectrometer at the outlet of the reactor, is equal to the retention time of radiolabelled ammonia in the catalyst bed. Thus, the radiolabelled ammonia moves with the saturation front, where aimnonia adsorption/desorption is in quasi equilibrium. We conclude that gas phase anunonia clearly facilitates desorption of [ Nj-NHs it remains adsorbed at the same bed position without ammonia in the gas phase. This proves that Adsorption Assisted Desorption takes place for aimnonia desorption from 7-alumina.

Au(lll) can be extracted from bromide-containing media with triphenylphospine sulfide dissolved in toluene. This permits separation from Cu(ll), Pb(II), Pd(ll) and Pt(lV). End analysis was by UW spectrophotometry . Separation of [Au(CN)2] from cyano complexes of other metal ions was performed by anion chromatography of the cyano complexes. The elution order of the various species depended on the concentration of sodium perchlorate in the eluting solution. Higher selectivity for gold was achieved when the eluant contained ammonia. Measurement was at 215 nm LOD 5 pg AuL using direct injection . 

Both kinds of quantity are needed if the yield of a chemical reaction is to be calculated under any particular conditons. Standard thermodynamic functions lead to standard equilibrium constants. Except at infinite dilution for gases or solutions, a condition of little importance in chemical industry, the properties of real mixtures are needed to calculate the yield from the standard equilibrium constant. No Haber-process chemist would keep his job for long who calculated the yield at 50 or 100 MPa from the standard equilibrium constant. Nor do we have even for mixtures of nitrogen + hydrogen + ammonia measured values of the properties needed. 

The MGA unit has been operated successfully at the Aliachem production site since September 1999 aqueous ammonia solutions of 27 wt% ammonia have been produced, and the emission of ammonia to the environment has been reduced by more than 99.9%. To detect this, a special ammonia measurement procedure had to be developed to measure the ammonia emissions [103]. 

The Lithuanian authorities reported some ammonia measurements on March 20, 1989 (Lithuanian State Committee for Environmental Protection, 1989). The largest measured concentration was 200 mg/m about 5 km downwind of the accident site at 3 00 to 4 30 p.m. UTC, and concentrations of about 20 to 25 mg/vo were measured at distances of from 5 to 12 km from the source. These values are not inconsistent with the concentration curves of release scenario 1 in Fig. 40.3. 

Ammonia measurements are made in the EMEP stations (Leinonen and Juntto, 1990) these inelude the concentration of NH components in the air and in bulk precipitation samples. Listed from north to south, the Finnish stations are Ahtari, Virolahti, and Uto. These are shown in Fig. 40.1. However, NH concentrations in the air were not available from the Uto station at the time, and daily measurements were not available from the Estonian stations (Syrve and Lahemaa). Both the concentration and precipitation samples are collected for 24 hours starting at 6 00 a.m. 

Analysis of filtered Baltic Sea samples of about 0.5 pmol/L spiked to nominally I, 2 and 3/tmol/L ammonia and analysed in three independent analytical runs resulted in a mean standard deviation of 0.092 pmol/L or 2.7 % Hansen and Johannsen, unpublished). Similar results have been reported by Riley et al. (1972) and Solorzano (1969). The recent ICES intercomparison exercise (Aminot and Kirkwood, 1995) showed an overall relative standard deviation of more than 20 %, indicating that, despite good precision of ammonia measurements within one laboratory, the inter-laboratory precision is comparatively poor. This is probably due to the ease of contamination in preparations of zero water and standards as well as in the handling of samples for ammonia determinations. 

The samples were prepared by adding 100 grams of plastic sample to 600 grams of mature soil compost in a 5-liter glass jar. The mature compost, 2-3 months old, had a pH of 8.7, ash content of 35%, and Carbon/Nitrogen (C/N) ratio of 10. The C/N ratio was calculated based upon carbon dioxide and ammonia measurements taken with the Sol vita instrument on the compost at the beginning of the test. Solvita is an easy-to-use test that measures both carbon dioxide (CO2) and ammonia (NH3) levels in the soil and also indicates a Maturity Index value. The index is useful for maturity level of the compost soil (Solvita Test Kit 2013). The blank compost had a Solvita overall maturity index of 7... 

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