Comparing HILIC and RPLC of Morphine Using Agilent ZORBAX RRHD Columns with UHPLC/MS

UHPLC/MS analyses of morphine and 3 of its metabolites (normorphine, morphine3-b-D-glucuronide [M3G], and morphine-6-b-D-glucuronide [M6G]) are used to compare mass spectrometer sensitivity with reversed-phase liquid chromatography (RPLC) and hydrophilic interaction chromatography (HILIC). Two Agilent ZORBAX Rapid Resolution High Definition (RRHD) columns are used in this comparison, an Agilent ZORBAX RRHD Eclipse Plus C18 for the RPLC method and an Agilent ZORBAX RRHD HILIC Plus for the HILIC method. Each is used with an Agilent 1290 Infinity LC System with an Agilent 6410A Triple Quadrupole Mass Spectrometer. Both methods use isocratic elution with an acetonitrile/ammonium acetate buffer mobile phase. Signal-to-noise calculations for the least sensitive M6G peak show HILIC mode allows for more sensitive MS detection due to more efficient spraying and desolvation in the ESI-MS source, as a result of the volatile acetonitrile rich mobile phase used.