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.