Carbon, hydrogen and nitrogen analysis

For inorganic and organic compounds the most common analysis undertaken is the determination of the amounts of carbon, hydrogen and nitrogen present. The usual method used is known as combustion analysis, where an accurately weighed amount of the compound is burnt in oxygen to form CO2, H2O, and N2 respectively. 

These are then selectively collected on weighed adsorbents, and the increase in mass of the adsorbent is determined. Note, however, that combustion analysis is a destructive technique, and can be expensive, and so it is often not employed until other characterization has taken place, and only then if you are publishing your work and have to prove beyond doubt that you can substantiate your claims. 

At some point in the near future you should watch the video entitled Combustion Analysis in the multimedia activity Practical techniques on the Experimental techniques CD-ROM that accompanies this book. The sequence shows the operation of a laboratory elemental analyser for C, H and N. This activity should take approximately 5 minutes to complete. 

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