Pyrolysis electron impact mass spectrometry in studying aquatic humic substances

Pyrolysis temperatures of complex biomaterials vary usually in the range 500–800 °C. By pyrolysis electron impact mass spectrometry (Py-EIMS) ionization energies are in general between 12 and 16 eV. Both the above variables influence the results significantly. Therefore, several experimental conditions were tested to fix the best values for these empirical parameters. The flash pyrolysis temperature of 510 °C and electron energy of 14 eV seemed to be a suitable combination for Py-EIMS and the fragments obtained are indicative of the types of organic structures released by humic substances under pyrolytic conditions.