Nitrogen analysers

Nitrogen analyses with this special rotator assembly are given in Table 3 for apparently pure samples of Ammonium Nitrate (AN),... 

To remove volatile impurities, the naterial was heated in vacuo at 135 °C. This treatment resulted in further condensation. Thus, the distillation residue was composed of a mixture of doubly-bridged dimers and tetramers, x = 1 and 2 as determined from the molecular weight, boron and nitrogen analyses and the volatile condensibles produced. 

Fig. 1.8 Elemental analysis supplied by Mitsubishi (a) TN-05 nitrogen analyser (b) TOX-10 total halogen analyser Source Own files...

Mitsubishi supply two total nitrogen analysers the model TN-10 and the model TN-05 microprocessor control chemiluminescence total nitrogen analysers (Fig. 1.8 (a)). 

Dohrmann also supply an automated nitrogen analyser with video display and data processing (model DN-1000) based on similar principles which is applicable to the determination of down to O.lmg L 1 nitrogen in solid and liquid samples. 

Extracts were further purified on neutral alumina cartridges conditioned by passing through 5 ml of hexane. Extracts were loaded in hexane and washed by 5 ml of hexane. The at- and /1-carotenes were removed by 3.5 ml of acetone-hexane (10 90, v/v), other carotenoids were eluted with acetone-hexane 30 70 and 70 30 v/v. Prepurification of pigments was performed in subdued light under a stream of nitrogen. Analyses were carried out in a C30 column (250 X 4.6 mm i.d., particle size 5/tm) using isocratic mobile phase composed of methyl-ferf-butyl ether (MTBE)-methanol (3 97 and 38 62, v/v) at a flow rate of 1 ml/min. The column was not thermostated separations were achieved at room temperature (about 23°C). Carotenoids were detected at 453 and 460 nm (lutein). The... 

A. Analysis of Wastewater and Natural Waters. The presence of certain anions in wastewater effluents can cause deterioration of natural water systems. Phosphorous and nitrogen can be present in several chemical forms in wastewaters. Phosphorous is usually present as phosphate, polyphosphate and organically-bound phosphorus. The nitrogen compounds of interest in wastewater characterization are ammonia, nitrite, nitrate and organic nitrogen. Analyses are often based on titrimetric, and colorimetric methods (3). These methods are time consuming and subject to a number of interferences. Ion Chromatography can be used to determine low ppm concentrations of these ions in less than thirty minutes with no sample preparation. 

Figure 12.12—Chemiluminescence reactions using ozone. Schematic showing the principle of a nitrogen analyser based on the luminescence of nitrogen monoxide.

Organic carbon analyses were made in duplicate by a combustion train method in the Microanalytical Laboratory, School of Chemistry, University of Minnesota, and Kjeldahl nitrogen analyses were done in triplicate in the Minnesota State Board of Health Laboratory. Averages of the readings are used here (Table III and VI) and are rounded off to the second decimal. Carbonate was removed from the samples by treatment with 0.5N hydrochloric acid prior to the carbon analyses. 

The authors thank E. A. Bevis for his technical assistance, R. C. D. Jones for performing many of the amino acid and nitrogen analyses, J. 

The precision of sulfur and nitrogen analyses was determined by multiple analysis of Raw Anthracene Oil and Synthoil liquid. The results of sulfur analysis of Raw Anthracene Oil were found to be precise within 0.25%. But the precision of other results was within 5.0%. 

Each sample was also characterized by elemental analysis. Accurate total nitrogen analyses were obtained using the semimicro Kjeldahl technique. 

That the combination of dilution with hexane and HC1 treating is more effective than dilution with hexane alone for precipitating nitrogen compounds in the product of hydroliquefaction is seen in Experiment 3, from the nitrogen analyses and yields of Schemes B and C extracts in Table VIII. In this experiment under conditions of relatively short contact time, the yield of extract in Scheme B products is close to that of the coal charged, indicating that essentially all of the liquefied coal is asphal-... 

The data in the table demonstrate that about half of the water-soluble ammonium ion content is converted into some new form of nitrogen, the nature of which has yet to be determined. Concurrent total nitrogen analyses by the use of a modified Kjeldahl procedure (0) capable of cleaving heterocyclic structures confirmed that no detectable amount of nitrogen had been lost from the phenolysis reaction system. 

The values in parentheses represent ratios in which the protein values were obtained by spectrophotometrio methods by the measurement of absorbance at 280 m/i and the use of empirical conversion factors, while for the other values the protein figures were determined by nitrogen analyses. 

Analyses. Oarbon, hydrogen, and nitrogen analyses were performed by Alfred Bernhardt, Max-Planck-Institute, Mulheim, Germany. 

It was ejq>ected that adsorption of polyaromatics on the surface would result in deactivation c the catalysts. When catalytic HDN and HDS occur, sulfur and nitrogen analyses may reveal whether this is the case. 

The other commonly used method in kinetic work is to measure the pressure rise during decomposition. Bircumshaw and Newman studied the decomposition of ammonium perchlorate using a McLeod gauge as the measuring device. They also studied the decomposition in a stream of nitrogen, analysing the products chemically by adsorption of CI2 in potassium iodide. For measurements in a stream of inert gas, a katharometer could be used as a detection device. Other methods of pressure measurement are also applicable, especially where a rapid reaction demands that a record be obtained. 

Copolymer compositions of poly(ACN-co-AN) and poly(ACN-co-MAN) were determined by elemental nitrogen analyses. The percentages of ACN in hydrocarbon copolymers were determined by UV spectroscopy, using the measured optical density for ACN in PACN at 310 nm in 1,2-dichloroethane as solvent. For poly(ACN-co-2VN) the compositions were checked by NMR spectroscopy (300 MHz). In all cases, conversions were held to ten percent or less in order to avoid drift in copolymer composition. 

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