Figure 1.

Ranking of 35 polar compounds (endogenous metabolites and exposome compounds) in human serum separated on an ACQUITY UPLC BEH Amide column (50 mm × 2.1 mm i.d.; 1.7 μm particle size) coupled to an ACQUITY UPLC BEH Amide VanGuard pre-column (5 mm × 2.1 mm i.d.; 1.7 μm particle size) under seven mobile phase modifiers in ESI(+). The analytes are sorted according to their predicted octanol/water partition coefficients (XlogP) obtained from the human metabolome database (hmdb.ca); the pH values are reported for the water solution (mobile phase A). Legend: AmF/FA, 10 mM ammonium formate and 0.125% formic acid; FA, 0.1% formic acid; AmF, 10 mM ammonium formate; AmAc, 10 mM ammonium acetate; AmAc/NH₄OH, 10 mM ammonium acetate and 0.01% ammonium hydroxide; AmBicarb, 10 mM ammonium bicarbonate; NH₄OH, 0.001% ammonium hydroxide.