No abstract

Improved apparatus and procedure are described for the determination of nitrogen b y combustion according to. the method of Dumas.The improvements permit a rapid, highly accurate analysis of organic materials, particularly petroleum products, containing 0.01 to 50% nitrogen, regardless of whether the sample is a gas, liquid, or solid. The possible incomplete combustion of methane formed b y thermal cracking is overcome by recycling a mixture of the combustion products and pure oxygen through the combustion tube until a constant residual volume is obtained. A n y organic residue remaining from the pyrolysis of the sample is completely oxidized by passing oxygen over the hot residue. The apparatus contains no rubber connections, allows adequate control of the combustion, and provides for accurate determination of the small amounts of nitrogen introduced by the carbon dioxide and oxygen. Means are described for preparetion of essentially nitrogen-free carbon dioxide. A skilled operator can make as many as eight determinations on liquid or solid samples or fifteen determinations on gas samples in an 8-hour day.11b: conventioriul Dumas combustion method for the deter-