Process and apparatus for determining total nitrogen content by

Abstract

This invention provides a process for determining the nitrogen content of a sample involving (a) combusting the sample in a combustion reactor in the presence of oxygen, which oxygen is introduced into the combustion reactor in pulse form; (b) reducing the resulting combustion gases by flowing them in a flow of helium or other noble carrier gas through a Cu-containing reduction reactor; (c) performing the steps of (i) making anhydrous in a water trap the reduced gases, (ii) flowing the reduced gases through a gas-chromatographic column in order to carry out a gas-chromatographic separation of N.sub.2 from CH.sub.4 possibly present within the reduced gases, and (iii) removing CO.sub.2 from the reduced gases using a CO.sub.2 trap, with the proviso that step (i) immediately precedes step (ii); and (d) analyzing the resulting gases by detecting thermal conductivity. This invention also provides an apparatus for determining the total nitrogen content of a sample which apparatus has a combustion reactor, a device for introducing oxygen into the combustion reactor in pulse form, a reduction reactor, a device for trapping water, a device for removing CO.sub.2 from combustion and carrier gases, a thermal conductivity detector, and a gas chromatographic column upstream of the detector packed with a material suitable to separate nitrogen from methane possibly present within the combustion gases.