Fig. 3: Characteristics of the core molecular community in AD.

a Principal component analysis (PCA) of DOM molecules in the PD and SD. b Percentage and relative abundance of the core molecular community. c Parallel plots for comparing compound classes, element combinations and NOSC between PD and SD samples. d Mass distribution, e Kendrick defect CH2 for the core molecular community. f (C-1-DBE)/C, g DBE/C and h AImod/C distribution for the core molecular community of PD and SD.