Determination of nitrogen, phosphorus and

Varley, J. A. Automatic Methods for the Determination of Nitrogen, Phosphorus and Potassium in Plant Material. Analyst 91, 119 (1966). 

For simultaneous determinations and /or speciation, different separation/ concentration steps can be implemented in the same manifold, as in, e.g., the determination of nitrogen, phosphorus and potassium in fertilisers [314]. The sample was inserted and passed successively through a dialysis unit and a gas diffusion unit to a flow cell for the spectrophotometric determination of phosphate. The dialysed potassium ions and the diffused gaseous ammonia were collected in specific streams and determined by flame photometry and potentiometry, respectively. 

P.B. Martelli, J.A. Gomes-Neto, E.A.G. Zagatto, S.M.B. Brienza, M.C.B.S.M. Montenegro, J.L.F.C. Lima, Sequential analyte removal in flow analysis determination of nitrogen, phosphorus and potassium in fertilizers, Anal. Chim. Acta 317 (1995) 239. 

Determination of nitrogen, phosphorus and silicon in particulate and dissolved organic matter... 

Kjeldahl flask Flask with pear-shaped bottom and long neck for the determination of nitrogen, phosphorus, and so forth by digestion in strong acids. 

Eaithfull, N.T. (1971a) Automated simultaneous determination of nitrogen, phosphorus, potassium and calcium on the same herbage digest solution. Laboratory Practice 20(1), 41 4. 

W. Maher, F. Krikowa, D. Wruck, H. Louie, T. Nguyen, and W. Y. Huang, Determination of Total Phosphorus and Nitrogen in Turbid Waters by Oxidation with Alkaline Potassium Peroxodisulfate, Anal. Chim. Acta 2002,463, 283. 

Maher, W. et al.. Determination of total phosphorus and nitrogen in turbid waters by oxidation with alkaline potassium peroxodisulfate and low pressure microwave digestion, autoclave heating or the use of closed vessels in a hot water bath Comparison with Kjeldahl digestion, Analytica Chimica Acta 463, 283, 2002. 

Aoyagi M., Yasumasa Y., and Nishida A. 1989. Simultaneous determination of total phosphorus and total nitrogen by flow injection system. Anal. Sci. 5 235-236. 

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. 

A comparative study on ylide stability as a function of the heteroatom type was carried out by Doering et al. [3,4]. They concluded that the phosphorus and sulfur ylides are the most stable ones. The participation of three-dimensional orbitals in the covalency determines the resonance stabilization of the phosphorus and sulfur ylides [5-8]. The nitrogen ylides are less stable from this point of view. The only stabilization factor involves electrostatic interactions between the two charges localized on adjacent nitrogen and carbon atoms [9]. 

In hospitals, chemical analysis is widely used to assist in the diagnosis of illness and in monitoring the condition of patients. In farming, the nature and level of fertiliser application is based upon information obtained by analysis of the soil to determine its content of the essential plant nutrients, nitrogen, phosphorus and potassium, and of the trace elements which are necessary for healthy plant growth. 

Barcelo D, Porte C, Cid J, Albaiges J (1990) Determination of organophosphorus compounds in Mediterranean coastal waters and biota samples using gas-chromatography with nitrogen-phosphorus and chemical ionization mass-spectrometric detection. Int J Environ Anal Chem 38(2) 199-209... 

De la Torre, R. et al. 1998. Quantitative determination of tricyclic antidepressnts and their metabolites in plasma by solid phase extraction (bond-elut TCA) and separation by capillary gas chromatography with nitrogen-phosphorus detection. Ther Drug Monit. 20 340. 

Suppliers of visible spectrophotometers are reviewed in Table 1.1. Spectroscopic methods are applicable to the determination of phenols, chlorophenols, amines, mixtures of organics, boron, halogens, total nitrogen and total phosphorus in soils, cationic surfactants, carbohydrates, total nitrogen, phosphorus and sulphur in non-saline sediments, boron, total organic carbon, total sulphur and arsenic in saline sediments, cationic surfactants, adenosine triphosphate and total organic carbon in sludges. 

This technique has found very limited applications in soil and sediment analysis and is particularly useful when routine automated analyses at the mg L 1 level of large numbers of samples is required. The technique has been applied to the determination of total phosphorus, total organic carbon and total nitrogen in soils, total organic carbon in non-saline sediments and total sulphur in saline sediments. 

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... 

Armstrong, F. A. J., and Tibbitts, S. (1968). Photochemical combustion of organic matter in sea water for nitrogen, phosphorus, and carbon determination. J. Mar. Biol. Assoc. UK 48, 143-152. 

Garcia-Repetto, R., I. Garrido, and M. Repetto (1996). Determination of organochlorine, organophosphorus and triazine pesticide residues in wine by gas chromatography with electron capture and nitrogen-phosphorus detection. J. Assoc. Off. Anal. Chem. Int., 79(6) 1423-1427. 

Henriksen, A. 1970. Determination of total nitrogen, phosphorus and iron in fresh water by photooxidation with ultraviolet radiation. Analyst 95 601-608. 

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). 

The physical and mechanical properties of steel depend on its microstructure, that is, the nature, distribution, and amounts of its metallographic constituents as distinct from its chemical composition. The amount and distribution of iron and iron carbide determine most of the properties, although most plain carbon steels also contain manganese, siUcon, phosphorus, sulfur, oxygen, and traces of nitrogen, hydrogen, and other chemical elements such as aluminum and copper. These elements may modify, to a certain extent, the main effects of iron and iron carbide, but the influence of iron carbide always predominates. This is tme even of medium alloy steels, which may contain considerable amounts of nickel, chromium, and molybdenum. 

Traditionally, gas chromatography (GC) was the preferred approach for the analysis of pollutants in water, due to the high sensitivity and selectivity achieved, thanks to its selective detectors such as the nitrogen-phosphorus (NPD), the flame photometric detector (FPD), and electron-capture detector (ECD), and to the ease of coupling to mass spectrometry (MS). However, high-performance liquid chromatography (HPLC or LC) is the most powerful approach for the determination of polar, nonvolatile, and thermolabile compounds (i.e., those which are not GC amenable). 

The determination of total phosphorus, total nitrogen, and organic carbon was introduced to the chemical monitoring programme of the IfM Warnemunde at selected stations in the 1980s. Since that time, investigations of harmful substances, such as heavy metals as well as chlorinated and petroleum hydrocarbons, started with special experiments and monitoring cruises. The details are shown in the relevant chapters. 

The nutrient distribution in the deepwaters of the central basins of the Baltic Sea is mainly determined by inflow events and stagnation periods characterized by strong variations in oxygen conditions. The general behavior of inorganic phosphorus and nitrogen compounds in the deep basins below the halocline and their reaction to Major Baltic Inflows (MBIs) is described in Chapter 10.6.2. In this chapter, the interaction between nutrients accumulated below the halocline and their influence on the surface layer and thus on eutrophication processes is studied in more detail. 

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. 

Sample dissolution and analyte conversion to a more easily detected species, e.g., the sequential injection determination of total nitrogen in wastewaters involving Kjeldahl oxidation and nitrate formation [141]. The spectrophotometric flow injection determination of organic phosphorus in natural waters [142], relying on the release of the different forms of phosphorus as orthophosphate, is another good example. 

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