 20 min High pH: Ionisation mode: Positive Electrospray. Acquity UPLC BEH C18 column (100 mm x 2.1 mm, 1.7 μm packing diameter) at 50 °C, 0.8 mL/min flow rate. Gradient elution with the eluents as 10 mM ammonium bicarbonate in water adjusted to pH 10 with ammonia solution and MeCN. The UV detection was a summed signal from wavelength of 210 nm to 500 nm. Injection volume: 0.2 µL. The elution conditions began with 1% MeCN mixture, increasing to 90% over 17 minutes, before remaining at 90% for 1.5 minutes, decreasing back to 1% MeCN mixture for 1.0 minutes before equilibrating for 1.0 minutes.