Liquid chromatography (conditions as reported by Zheng et al. ) was performed on a Nexera UHPLC (Shimadzu Corporation, Kyoto, Japan) composed of one LC-30AD pump, a SIL-30AC autosampler and a CTO-30A oven. The UHPLC system was coupled to an LCMS-8060 triple quadrupole mass spectrometer equipped with an ESI source and a prototype vDMS cell operating at a pressure of 33 mbar (Shimadzu Research Laboratory, UK). The nebulizing gas flow was of 1.5 L/min (N2), the drying gas flow of 3.0 L/min (N2), and the heating gas flow of 3.0 L/min (Air). The interface voltage was 2 kV and temperature 200°C, the DL temperature of 200 °C, and the heat block temperature of 400 °C.. For LC-MRM/MS analysis Argon was used as CID gas (270 kPa) and the vDMS was switched off.