Processing and Interpreting Mass Spectral Data in Forensic Identification of Drugs and Explosives

Abstract

Abstract Mass spectrometry has become a well-established analytical method in the forensic identification of drugs and explosives [1,2]. In electron impact (EI) mass spectrometry (MS) the investigated sample is ionized by an electron beam having an energy of 70 eV. Because of this high ionization energy, the ions, after their formation, will usually decompose to fragmentation products including both charged and neutral species. The complexity of the EI mass spectrum, while often an important asset because of its “fingerprint” value, is clearly a disadvantage when complex mixtures are to be analyzed. When the compound is more complex, the amount of fragment ions is larger and the chances of observing a molecular ion are smaller. Electron impact mass spectrometry can be applied to mixtures, but only after separation, usually performed by a gas chromatograph-MS combination.