Determination of nitrogen and

U.S. EPA, Method SCI-Determination of Nitrogen- and Phosphorus Containing Pesticides in Ground Water hy GCj NPD, draft, Apr. 15, 1988 available from U.S. EPA Environmental Monitoring and Support Laboratory, Cincinnati, Ohio, 1988. 

B. Langfoid and I. H. Stice, The Determination of Nitrogen and Oxygen by Inert Gas Fusion, Teledyne Wab Chang Corp., Albany, Oieg., 1994. 

The effect of storage of water samples before determination of nitrogen and carbon associated with particulate matter was investigated. Freezing of the samples, and storage at 5°C, both affected the results obtained, but changes were minimized if the samples were filtered immediately after collection and the particulate matter stored on the filter paper. It is recommended that samples for determination of particulate carbon and nitrogen should be filtered immediately, and analysed as soon as possible. 

Pelts and Belcher [46] have described a semi-automated method for the simultaneous determination of nitrogen and phosphorus in soil. Up to 40 samples are digested with sulphuric acid using a copper sulphate-sodium sulphate catalyst at 370°C for 2.25h in a thermostatically controlled block. Nitrogen is then determined in the 0.2-2.25% range as ammonia by automatic colorimetric analyses of the indophenol blue complex at 630nm. 

Edgell KW, Jenkins EL, Lopez-Avila V, et al. 1991. Capillary column gas chromatography with nitrogen-phosphorus detection for determination of nitrogen- and phosphorus-containing pesticides in finished drinking waters Collaborative study. J Assoc Off Anal Chem 74 295-309. 

For the determination of nitrogen- and phosphorus-containing pesticides in water by extraction with dichloromethane and detection by GC-NPD... 

Determination of Nitrogen- and Phosphorus-Containing Pesticides in Water by GC with a Nitrogen-Phosphorus... 

By means of a pipette add 5 ml. of the monochloroamine solution to a small flask containing 25 ml. of a cold sodium bisulfite solution. A moderate excess of sulfite is necessary. Stopper the flask, and shake gently. When the reaction is complete, remove the ether with a separatory funnel or by warming. Dilute the sulfite solution to 100 ml., and use aliquot portions for the determination of nitrogen and chlorine. 

Bryan, F. R., Bonfiglio, S. Determination of nitrogen and oxygen in steels using inert gas fusion chromatography. J. Gas Chromatog. 2, 97 (1964). 

Hargrove, G. L., Shepard, R. C., Farrar, V. H. Determination of nitrogen and hydrogen at parts-per-million levels in milligram steel samples. Anal. Chem. 43, 439 (1971). 

G. Verga, High resolution gas chromatographic determination of nitrogen and phosphorus compounds in complex organic mixtures by tunable selective thermionic detector, J. Chromatogr., 279 657-665 (1983). 

In summary, the methods developed using ICPES and IC, and other thermal decomposition procedures for metals and nonmetals, are now routinely used at Exxon s Baytown Research and Development Division for the characterization of a large number of oil shales and shale products with precision and accuracy of 1-5 percent. Problems remain with the determinations of nitrogen and sulfur forms in oil shales. 

J.W.B. Stewart, J. Ruzicka, Flow injection analysis. Part V. Simultaneous determination of nitrogen and phosphorus in acid digests of plant material with a single spectrophotometer, Anal. Chim. Acta 82 (1976) 137. 

The chemical conversions involved in the operation of GC elemental analysers have been thoroughly studied in order to evolve methods for the determination of nitrogen and to develop CHN analysers. 

Recently, the determination of nitrogen and especially of phospliorus has become particularly important because of their ever increasing amounts in natural waters. An excessive content of these important biogenous elements... 

J. W. B. Stewart and J. Rdiidka, Flow Injection Analysis. Part V. Simultaneous Determination of Nitrogen and Phosphorous in Acid Digests of Plant Material with a Single Spectrophotometer. Anal. Chim. Acta, 82 (1976) 137. 

The Introscan system described above has been extended to use specific detectors, for example, for the selective determination of nitrogen and halogen compounds. 

Let us focus on the WCOT columns used to implement EPA Method 507 Determination of Nitrogen- and Phosphorus-Containing Pesticides in Water by GC with a Nitrogen-Phosphorous Detector . The method is summarized as follows (50) ... 

FI systems have been successfully used with spec-trophotometric detection, for example, for the determination of nitrogen and phosphorus species in rivers and streams. It has also been used to determine anionic surfactants (e.g., sodium lauryl sulfate, sodium dodecyl sulfonate), chloride, and organophos-phoric insecticides in freshwater bodies. FI also can be coupled with other analytical techniques for sample introduction purposes. Such methods include FI coupled with atomic absorption spectrometry for online preconcentration and separation of chromium species and with mass spectrometry for the determination of polar organic pollutants. 

Small quantities of nitrate may be estimated colorimetrically either with (a) phenoldisulphonic acid or ( ) 2,4-xylenol. Reduction with Devarda alloy or aluminium foil can also be used (see under Determination of Nitrogen) and the ammonia produced determined with Nessler s reagent. 

Table VI-4 Nuclear reactions for the determination of nitrogen and nuclear interferences (Threshold energies in MeV)...

Oxidizing fusion is more reliable and of more general use than the Kjeldahl method and can be used to analyze larger amounts of sodium (5 to 7 g). An additional advantage is that it allows the determination of nitrogen and carbon simultaneously. 

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