Identification of Morphine and Morphine-6-Glucuronide in the Adrenal Medullary Chromaffin PC-12 Cell Line by Nano-Electrospray Ionization Double Quadrupole Orthogonal-Acceleration Time-of-Flight Mass Spectrometry

Using nano-electrospray ionization double quadrupole orthogonal-acceleration time-of-flight mass spectrometry, we were able to detect sub-nanogram levels of endogenous morphine and its metabolite morphine-6-glucuronide in the rat pheochromocytoma cell line. Furthermore, fragmentation of endogenous morphine-6-glucuronide (462.14 Da) by collision-induced dissociation yields morphine (286.14 Da) obtained from the cell samples and with the authentic material, further demonstrating the presence of endogenous morphine. The incubation medium was devoid of this material. This methodology represents a sensitive and accurate method to detect trace amounts of endogenous opiates at subnanogram levels in biological samples.