TABLE OF CONTENTS Since all organic compounds contain carbon and hydrogen, and a large number of them also additionally contain nitrogen, it can be seen that the ability to measure these elements accurately is of extreme importance for characterization and identification of such organic compounds. The microcombustion technique is the principal means for determining carbon, hydrogen, and nitrogen. Automated elemental analyzers that are commercially available offer multisample and unattended operation. The combustion operation is completely automated and is followed by an on-line measurement of the components in the combustion gases. Computerization permits extensive data reduction, calculation, reporting, and storage capabilities. The technique involves several steps.
1. In the purge mode, the weighed sample is dropped into the loading head, which is then sealed and all the interfering gases are purged from the combustion path.
2. In the burn mode, the sample is moved onto a ceramic crucible and into the furnace for combustion in a flowing stream of pure oxygen at 900 C. The sample boat can subsequently be removed for weighing any residue. Alternatively, the sample can be mixed with cobalt(III) oxide [or a mixture of manganese dioxide and tungsten(VI) oxide] to provide the oxygen and heated to the same combustion temperature. Carbon dioxide, water vapor, nitrogen and some oxides of nitrogen, and oxides of sulfur are possible products of combustion of an organic compound. The burn time is 10 to 12 min.
3. The removal of interfering elements is effected.
4.
