The LOD after propionylation of 6-AM with propionic anhydride and pyridine was found to be 3 [micro]g/L compared with 0.5 [micro]g/L for the pentafluoropropionyl derivative. The monitored ions for 6-AM were m/z 384 ([M.sup.+] + 1), 383 ([M.sup.+]), and 324; and for [d.sub.6] AM, the monitored ions were m/z 389 ([M.sup.+]) and 333.
GC-MS conditions for pentafluoropropionyl derivatives. The instrument was operated in splitless and temperature program mode.
The procedure described in Materials and Methods was designed to detect free codeine, free morphine, and 6-AM simultaneously as the pentafluoropropionyl derivatives. Because the concentrations of free morphine and free codeine generally are much higher than that of 6-AM, the derivatized extract was analyzed by two separate injection modes.