Separations for the ion spectroscopy experiments were performed using a Bruker Elute UHPLC system consisting of a binary pump, cooled autosampler and a column oven. MS detection was performed using a 3D ion trap mass spectrometer (Bruker, AmaZon Speed ETD). The column was a Waters XBridge BEH phenyl column (150 × 3.0 mm i.d., 2.5 μm particles, 130 Å pore size) and the mobile phase consisted of 10 mM ammonium acetate in H2O/ACN 95:5 [v/v] (mobile phase A) and ACN/MeOH 80:20 [v/v] (mobile phase B). The column was held at 40 C° and a flow-rate of 1 ml/min and sample injection volumes of 2 µl were used. After an initial time of 0.9 minute at 95% A, a gradient of 7.7 min was run to 95% B, followed by a hold at 95% B for 2.4 min. The column was equilibrated for 2 min between injections.