First ionization potential inorganic

I knew that molecular N2 did not interact with PtFe, since I had prepared samples of PtFe using F2 diluted with N2. This was not surprising since the first ionization potential of N2 is 15.58 eV. Because NF3 had a listed ionization potential ( 13 eV), less than 1 eV higher than that of O2, I did examine its interaction with PtFe, but found no sign of NF3 oxidation. Then, in early February 1962, as I was preparing a lecture for my senior undergraduate class in Inorganic Chemistry, I was suddenly reminded of an important Periodic Table trend. 

The first ionization potential may prove useful in sorting out and ordering the data for binaries of inorganic compounds, but it is certainly of little use in the prediction of ky s for hydrocarbon-hydrocarbon binaries. For example, the I of n-pentane (10.55 eV) is very similar to that of ethylene (10.51 eV), but the kys for the n-pentane binaries are markedly lower than those for the corresponding ethylene binaries (4). On the other hand, the ethylene and ethane binaries have similar kys (Figure 2), even though the I of ethane is 1.25 eV higher than for ethylene (20). 

The first aim of sample preparation is the removal of potential interferences. For example, inorganic salts need to be removed from the sample before analysis by mass spectrometry, as they suppress ionization of organic analytes and reduce sensitivity. For analyzing small molecules, such as drugs, fatty acids, and sugar phosphates, proteins and glycoproteins need to be removed. 

---