Volume 20, Issue 2 (April 1975)
A Comparison of Some Mass Spectrometric Ionization Techniques Using Samples of Morphine and Illegal Heroin
The precise identification of drugs in body fluids or in illegal preparations may be accomplished by the relatively sophisticated techniques of mass spectrometry [1,2] or gas chromatography-mass spectrometry [2,3]. The application of these techniques to drug analysis is well documented [4–6]. Recently, more attention has been paid to the type of mass spectra produced by different methods of ionization . The most useful mass spectrum for many applications is one in which the molecular ion is large and unambiguous. However, some fragmentation is often a desirable feature because this may help to confirm the identity of a compound, differentiate isomers, or assist in elucidating the structure of an unknown. High pressure ionization methods have been found to be particularly useful for drug identification since they often produce the base peak of the spectrum in the molecular ion region, thus serving to identify the molecular weight of the compound. However, some compounds, notably heroin and morphine, fragment easily when ionized with the high pressure reagent gases used so far.