CHN Determination of Highly Fluorinated Organic Compounds

To accurately determine the percentage Carbon (C), Hydrogen (H) and Nitrogen (N) in highly fluorinated organic compounds**, Exeter Analytical Inc. has developed a reliable analytical method using their Model 440 Elemental Analyzer.

Generally compounds containing fluorine can be successfully analysed for percentage CHN content on most elemental microanalysis systems under standard operating conditions. The magnesium oxide in the combustion tube reagent packing absorbs fluorine as HF, and releases the hydrogen. However - highly fluorinated compounds, which are often difficult to combust, can give incorrect carbon and high nitrogen data. This is believed to be due to the strength of the C-F bond. If not fully oxidized, CF2 passes through the combustion tube packing and is detected as nitrogen, resulting in both low carbon and high nitrogen data.

For these highly fluorinated compounds, Exeter Analytical have developed a new reliable analytical method based upon their Model 440 Elemental Analyzer that is described in Application Note 217.