UPLC-MS was performed on a Waters Acquity I-Class with Waters Diode Array Detector coupled to a Waters SQD2 single quadrupole mass spectrometer using an Waters HSS C18 column (1.8 µm, 100 × 2.1 mm) or on a Waters DAD + Waters SQD2, single quadrupole UPLC-MS spectrometer using an Acquity UPLC BEH Shield RP18 1.7um 100 x 2.1mm (plus guard cartridge), maintained at 40 °C. The columns were initially held at 5% acetonitrile/water (with 0.1% formic acid or 10 mM ammonium bicarbonate in each mobile phase), followed by a linear gradient of 5-100% and then held at 100%.