'Metabolic mapping' of drugs: rapid screening techniques for xenobiotic metabolites with m.s./m.s. techniques.

The development of tandem mass spectrometry (m.s./m.s.) techniques for the rapid structural elucidation and quantification of metabolites is described. With these techniques the mass spectrometer serves as both a separation device as well as a tool for structure elucidation. Ion formation by desorption ionization techniques and mass analysis with an appropriate combination of neutral loss and precursor ion scans can then be used to classify the number and type of primary metabolites and polar drug conjugates that are present in a complex sample matrix. The resulting information can be used to assess the overall biotransformation routes that are available to a drug or other xenobiotic substance.