Nitrogen analysis Dumas method

Drop volume tensiometer (DVT), for interfacial tension, 636-638 DSA. see Drop shape analysis Dumas method, nitrogen content... 

Total nitrogen determinations in barley and malt gave slightly higher results by the Dumas than by the Kjeldahl method. The Dumas method was adopted as the reference method by the Analysis Committee of the Institute of Brewing27. Comparison of the results obtained by the Kjeldahl method with those of automatic N analyzers is mentioned in Section III.A.2 above. 

The determination of nitrogen in petroleum products is performed regularly by the Kjeldahl method (ASTM D3228), the Dumas method, and the microcoulomet-ric (ASTM D3431) method. The chemiluminescence method is the most recent technique applied to nibogen analysis for petroleum and is used to determine the amount of chemically bound nitrogen in liquid samples. 

Dumas method A method of analysis based on the combustion of nitrogen-containing organic samples by CuO to convert the nitrogen to N2, which is then measured volumetrically. 

Figure 18.4 Instrument for nitrogen analysis. This instrument is a modern adaptation of the Dumas method, with the conventional detection hy means of a catharometer (He is the carrier gas).

The foregoing method has a number of important advantages it provides for a rapid and accurate determination of nitrogen it helps to increase the accuracy and precision of the analytical method and it provides for accurate analysis of compounds that are bound to introduce large errors if analysed according to the Dumas method. 

Figure 1 Crude protein determination by the Dumas method for total nitrogen with the LECO apparatus. (Reproduced from O Keeffe M (1992) Chemical analysis of animal feed and human food. In Smyth MR (ed.) Chemical Analysis in Complex Matrices, pp. 241-287. Chichester Ellis Horwood.)...

The standard procedure of nitrogen determination by many laboratories is the Kjeldahl method (ASTM D-3179 ISO 333), although there are the standard methods that involve the Dumas technique (DIN 51722) and the gasification procedure (DIN 15722). Neutron activation analysis has also been proposed for the determination of nitrogen in coal, coal ash, and related products (Volborth, 1979a). 

The quantitative elemental analysis of organic compounds, perfected by Liebig for carbon and hydrogen in 1831 and by Dumas for nitrogen in 1834, has been described in Chapter 8. An alternative method for the determination of nitrogen was devised in 1883 by Johan Kjeldahl (1849-1900) in which the element is converted to ammonia, which is then determined by titration. The standard... 

Jean Baptiste Andre Dumas (1800 1884) was a teacher, chemist, and French public servant whose name is still associated with analytical methods for both the determination of nitrogen by combustion analysis and vapor density. 

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