Fig. 2 Comparison of AImod and AImod’ with actual data (organics with
AImod or AImod’≥0.67 are classified as condensed aromatics, and those
with 0.5≤AImod or AImod’ <0.67 are categorized as aromatics)
According to the structures of the 2235 organics, a comparison between
AImod and AImod’ was chosen to determine the validity of the adjusted
aromatic indexes (as shown in Fig. 2). The proportions of condensed
aromatics and aromatics predicted by AImod’ are closer to the actual
data than those predicted by AImod.
In summary, introducing halogen to the interpretation models of HRMS
data for organic matter improves the accuracy. The modified van Krevelen
diagram, NOSC and aromatic indexes are equivalent for multiple organic
matter, including NOM, emerging environmental pollutants, and artificial
products.