For cationic profiling, ESI was operated in positive mode with the following MS parameters: nebulizer and sheath gas were set to 0 bar and 10 L/min, 100 • C, respectively. Capillary, end-plate and funnel voltages were respectively adjusted to 6000, 400 and 300 V. For anionic profiling, ESI was performed in negative mode with the following source parameters: nebulizing gas and sheath gas were set to 0.3 bar and 4 L/min, 150 • C respectively. Capillary, end-plate and funnel voltages were adjusted to 4000, 400 and 300 V, respectively. MS acquisitions were performed at a frequency of 1 Hz, with a mass range going from 50 to 1000m/z.